Knowledge base v2.13.0 · Community edition · data through 2 October 2026
Topic · Structured data and media
Attendees were told on Day 1 to check ARIA and accessibility, and Google's guide for generative AI features says browser agents may read a page through screenshots, the DOM and the accessibility tree, and recommends semantic HTML because it also helps screen reader users. Day 2 added that Gemini in Chrome relies heavily on the screenshot it takes of a page (the Gemini in Chrome detail was said at the event). Day 2 also tied accessibility to images and translation: alt text should describe an image for someone who cannot see it, and Google's image guide calls alt the most important attribute for image metadata; John Mueller said he dislikes notranslate because automatic translation is a form of accessibility, and that the meta tag named google also turns off Chrome's translation (not in Google Search's current docs; Chromium's Translate design document describes the same opt-out). A community speaker said embedding applications in iframes brings accessibility, layout and navigation problems. Author’s view: Google has not called ARIA a ranking signal; the case for accessible markup is that assistive tools, browser agents and Google's image understanding read the same page, even if some agents lean on screenshots. A second recording of Day 1 captured a community talk on preparing sites for agents: agents combine a screenshot, the DOM and the accessibility tree, so a div with no semantic HTML or landmarks has no purpose an agent can tell; the speaker recommended landmark elements (header, nav, main, article, footer), a logical heading order and ARIA attributes such as role=button, aria-label and aria-pressed on custom controls, warning that no ARIA is better than bad ARIA. Google's SEO Starter Guide says semantic heading order helps screen readers but does not matter to Search. On Day 2 a community speaker showed LLM-written alt text that described only what a model could see, a cat and a vet, and dropped the page's meaning, and advised testing on a few URLs and giving the model the page's title.
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A community speaker said AI agents understand a page through a combination of three inputs: a screenshot, the DOM (the HTML plus the changes rendered by JavaScript) and the accessibility tree.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Used byrequirement DEV-HTM-04
A community speaker advised keeping headings inside the main content in a logical hierarchy (title, section subtitles, subsections) so agents can follow its structure, avoiding several H1 elements and skipped levels such as an H3 followed directly by an H5.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Used byrequirement DEV-HTM-04
A community speaker said a block of content without semantic HTML or landmarks is just a div whose purpose an agent cannot tell, and recommended landmark elements (header, nav, main, article for independent sections, footer) plus p and h1-h6 for text.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Used byrequirement DEV-HTM-04
A community speaker described ARIA (Accessible Rich Internet Applications) as a set of attributes, not a programming language, that adds accessibility information to HTML: a div used as an 'add to favourites' button can get role=button, an aria-label and aria-pressed set to true or false.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Used byrequirement DEV-HTM-04glossary term ARIA
A community speaker warned that no ARIA is better than bad ARIA: wrong or confusing ARIA attributes do more harm than leaving them out.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Used byrequirement DEV-HTM-04glossary term ARIA
A community speaker summed up agent readiness in three layers: a good CLS improves how agents see content, schema, landmarks and ARIA how they understand it, and WebMCP how they interact with it.
Speaker Carlos OrtegaIn Day 1, 13:10 · Lightning session A: Automation and AIEvidence transcript
Attendees were told to check ARIA and accessibility.
In Day 1 · session not recordedEvidence notes, transcript
Used byrequirement DEV-HTM-04
Google's SEO Starter Guide says headings in semantic order help screen readers but do not matter to Google Search if used out of order, and that there is no ideal number of headings for a page.
Publisher Google Search CentralAnnotates Day 1, 13:10 · Lightning session A: Automation and AI
Used byrequirement DEV-HTM-04
Google's guide for generative AI features says browser agents may read a site through screenshots, the DOM structure and the accessibility tree, and recommends semantic HTML because it helps users such as screen reader users navigate a page.
Publisher Google Search CentralAnnotates Day 1 · session not recorded
Used byrequirement DEV-HTM-04
A logical heading hierarchy is not a Google Search requirement, since Google says out-of-order headings do not matter to Search; the case for it is accessibility, where web.dev advises against skipping levels, and agents that read the accessibility tree.
Author Ibrahim AnjroAnnotates Day 1, 13:10 · Lightning session A: Automation and AI
Google has not called ARIA a ranking signal. The case for it is that AI agents and assistive tools read pages through the same structure: real buttons, labelled forms and semantic headings.
Author Ibrahim AnjroAnnotates Day 1 · session not recorded
Used byrequirement DEV-HTM-04
An iframe, the long-established way to embed an app, isolates both JavaScript and styles but is not part of the page: it is walled off from the host's DOM, navigation and layout, which Natalia Venditto said brings many problems with accessibility, layout and navigation.
“Walled off from DOM, navigation, layout”
Wording checked against the slide or recording
Speaker Natalia VendittoIn Day 2, 10:40 · Lightning session D: Rendering and JavaScriptEvidence slide photo, transcript
John Mueller said notranslate can also be set in a meta tag named google, and that in that form it also turns off Chrome's automatic translation of the page.
Speaker John MuellerIn Day 2, 10:30 · Controlling indexingEvidence transcript
Used byrequirement DEV-IDX-09
John Mueller said he dislikes notranslate because automatic translation is a form of accessibility for visitors who cannot read the page's language.
Speaker John MuellerIn Day 2, 10:30 · Controlling indexingEvidence transcript
Alt text should describe the image in words for someone who cannot see it.
Speaker Gary IllyesIn Day 2, 13:50 · Using images to your advantage and Engaging Search users with videosEvidence transcript
Used byrequirement DEV-IMG-02
Version 20 of the Screaming Frog SEO Spider, released in May 2024, was the first that could connect the crawler to ChatGPT through custom JavaScript, which let SEOs rewrite image alt text at scale.
Speaker not identifiedIn Day 2, 14:00 · Lightning session F: MediaEvidence transcript
In a community speaker's case, an LLM asked to write alt text for a product image of a veterinary anxiety medicine for cats described only what it could see, a cat and a veterinarian, and dropped the stress, anxiety and medical-treatment intent of the page.
Speaker not identifiedIn Day 2, 14:00 · Lightning session F: MediaEvidence transcript
To test LLM-generated alt text before a rollout, a community speaker recommended running the crawler's custom JavaScript in Screaming Frog's List mode on a few chosen URLs and reviewing the generated alt text, instead of crawling the whole site in Spider mode.
Speaker not identifiedIn Day 2, 14:00 · Lightning session F: MediaEvidence transcript
Used byrequirement DEV-IMG-02
Because not every generated alt text can be checked by hand, a community speaker's safer script adds the page title to the LLM's image description, so the alt text carries the page's intent and not only what the image shows.
Speaker not identifiedIn Day 2, 14:00 · Lightning session F: MediaEvidence transcript
Used byrequirement DEV-IMG-02
A community speaker cited W3C guidance that, when cleaning a transcript, it is usually not appropriate to correct the speaker's grammar or other mistakes.
Speaker Patrick DomanicoIn Day 2, 14:00 · Lightning session F: MediaEvidence transcript
Google's image SEO guide calls alt text the most important attribute for providing more metadata about an image, and says Google uses it together with computer vision and the page content to understand the image.
“The most important attribute when it comes to providing more metadata for an image is the alt text”
Publisher Google Search CentralAnnotates Day 2, 13:50 · Using images to your advantage and Engaging Search users with videos
Used byrequirement DEV-IMG-02
International sites should remove notranslate from their templates unless translation must be prevented: the robots or googlebot form switches off Google Search's translation features, and John Mueller said the form named google also blocks Chrome's translation for visitors who do not read the language.
Author Ibrahim AnjroAnnotates Day 2, 10:30 · Controlling indexing
Used byrequirement DEV-IDX-09
Before embedding an app or widget in an iframe, test it with a keyboard and a screen reader as well as for layout and navigation, because the isolation an iframe gives comes at those costs.
Author Ibrahim AnjroAnnotates Day 2, 10:40 · Lightning session D: Rendering and JavaScript
Give important images a caption or explanatory sentence next to them rather than relying on alt text alone, since Gary Illyes ranked src above alt and called the surrounding text critical for ranking the image.
Author Ibrahim AnjroAnnotates Day 2, 13:50 · Using images to your advantage and Engaging Search users with videos
Used byrequirement DEV-IMG-03
A community speaker said a block of content without semantic HTML or landmarks is just a div whose purpose an agent cannot tell, and recommended landmark elements (header, nav, main, article for independent sections, footer) plus p and h1-h6 for text.
Google's guide for generative AI features says browser agents may read a site through screenshots, the DOM structure and the accessibility tree, and recommends semantic HTML because it helps users such as screen reader users navigate a page.
A community speaker described ARIA (Accessible Rich Internet Applications) as a set of attributes, not a programming language, that adds accessibility information to HTML: a div used as an 'add to favourites' button can get role=button, an aria-label and aria-pressed set to true or false.
A logical heading hierarchy is not a Google Search requirement, since Google says out-of-order headings do not matter to Search; the case for it is accessibility, where web.dev advises against skipping levels, and agents that read the accessibility tree.
A community speaker advised keeping headings inside the main content in a logical hierarchy (title, section subtitles, subsections) so agents can follow its structure, avoiding several H1 elements and skipped levels such as an H3 followed directly by an H5.
Google's duplication talk closed with the advice not to block agents, which the speaker said are sometimes really cool.
Google's guide for generative AI features says browser agents may read a site through screenshots, the DOM structure and the accessibility tree, and recommends semantic HTML because it helps users such as screen reader users navigate a page.
Gemini in Chrome relies heavily on the screenshot it takes of a page.
Google's guide for generative AI features says browser agents may read a site through screenshots, the DOM structure and the accessibility tree, and recommends semantic HTML because it helps users such as screen reader users navigate a page.
In a community speaker's case, an LLM asked to write alt text for a product image of a veterinary anxiety medicine for cats described only what it could see, a cat and a veterinarian, and dropped the stress, anxiety and medical-treatment intent of the page.
Google's guidance on generative AI content warns that AI output can contain hallucinations and says AI-generated metadata, including structured data and image alt text, should be fact-checked before publishing and the markup validated.
Because not every generated alt text can be checked by hand, a community speaker's safer script adds the page title to the LLM's image description, so the alt text carries the page's intent and not only what the image shows.
The text around an image is critical: Google uses it as context to understand the image and to rank it, so an alt attribute alone is not enough.
A community speaker said AI agents understand a page through a combination of three inputs: a screenshot, the DOM (the HTML plus the changes rendered by JavaScript) and the accessibility tree.
Google's guide for generative AI features says browser agents may read a site through screenshots, the DOM structure and the accessibility tree, and recommends semantic HTML because it helps users such as screen reader users navigate a page.
Use semantic, accessible HTML: real buttons, labelled forms and a logical heading order
Rests on 10 claims, 9 of them in this topic
Describe every meaningful image in its alt attribute
Rests on 5 claims, 4 of them in this topic
Rests on 8 claims, 2 of them in this topic
Place images next to text that explains them
Rests on 3 claims, 1 of them in this topic