chrome://browser/content/blanktab.html not handled as blank tab

[iacore]

Steps to reproduce

• Install Librewolf and use it a bit
• (browser settings) Set "Home page and new windows" to "Blank Page"
• Install Sidebery
• Open a new browser

Expected behavior

New Tab Icon is firefox icon

Actual behavior

New Tab Icon is some random icon from a previous site that you have browsed. This is likely a Librewolf stale data bug, although I would like Sideberry to handle this as well.

Debug info

On Librewolf, the default blank tab is chrome://browser/content/blanktab.html, which is the same as about:newtab. I tried to fix this issue myself, but couldn't find where to fix. (getFavPlaceholder isn't even called since the page has a random nav icon.)

Workaround

• (browser settings) Set "Home page and new windows" to "Custom URL" about:newtab