I am currently making an extension, and I hope I could get some practical advice on feasibility :
I want my extension to go fetch/load a local folder of custom homescreen thumbnails(top-sites), and then replace the auto-generated thumbnails in the homescreen with those it loaded. The extension would be able to read the associated domain names of the thumbnails and then replace them accordingly.
(e.g :Pinned Url : youtube.com/anything : Ok so it’s YouTube : then replace the thumbnail with “Custom_Youtube_Thumbnail.png”)
Does that seems possible to you ? (Before I dive in head first) I saw that the top-sites API is not quite available https://bugzilla.mozilla.org/show_bug.cgi?id=1246693 but maybe I’m wrong.
Extra : My extension is switching themes (like this : https://github.com/mdn/webextensions-examples/tree/master/theme-switcher ). Would it be possible to switch the thumbnails accordingly (Custom_Youtube_Thumbnail_light.png > Custom_Youtube_Thumbnail_dark.png) as i’ve made a version for each.
Would be a pleasure to hear your opinion on this, or just pointing useful resources to me, I’m not asking for a perfectly baked solution. Hope I’ve been concise.
Thanks for reading me !
Very nice idea you had. But In short: no possible.
Main problem is that you cannot inject and manipulate on the homepage which is a built in browser tab.
"You cannot inject code into any of the browser's built-in pages, such as: about:debugging, about:addons, or the page that opens when you open a new empty tab." https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/tabs/executeScript