'Google, making the announcement in a blog post:

We're updating the way Google Docs renders documents. Over the course of the next several months, we'll be migrating the underlying technical implementation of Docs from the current HTML-based rendering approach to a canvas-based approach to improve performance and improve consistency in how content appears across different platforms. We don't expect this change to impact the functionality of the features in Docs. However, this may impact some Chrome extensions, where they may no longer work as intended.

Some Chrome extensions rely on the way the backend of a Google Doc is structured or specific bits of HTML to function properly. By moving away from HTML-based rendering to a canvas-based rendering, some Chrome extensions may not function as intended on docs.google.com and may need to be updated. Admins should review the current extensions deployed in their organization. [...] If you are building your own integrations with Google Docs, we recommend using Google Workspace Add-ons framework, which uses the supported Workspace APIs and integration points. This will help ensure there will be less work in the future to support periodic UI implementation changes to Docs.'

-- source: https://tech.slashdot.org/story/21/05/12/165216

Cheers, Peter