[Bug] Extendium crashes / fails to install on Millennium Beta 3.0

[BossSloth]

Multiple users have reported being unable to install Extendium 2.0 on Millennium Beta 3.0.
I'm opening this issue to combine reports and gather more information, as i have not been able to reproduce this myself.

Important

If you are getting this error update to the latest version of Extendium from the GitHub Releases Installing it via the plugin id will only work if you are not on the Millennium beta.

Failed to install

If you are having issues with installing Extendium 2.0 because it is crashing or the Extendium button not appearing.
Please leave a comment with:

• Your extendium version
• Your millennium version
• Full error logs if you are getting any

[Maikoli]

Works just fine when using the GitHub version, (even the puzzle icon is there with 2.0.3) but why aren't you updating the version on Steambrew? Really 100% neutral question, I am just wondering.

[BossSloth]

@Maikoli The reason why I haven't updated the one on Steambrew is because I have been getting almost daily notifications of people crashing with the new version, that's why I created this issue to collect some useful logs instead of just "same". As the non 2.0 version works perfectly fine on non beta Millennium so I want it to still work for those users.
If I don't see anyone reporting that it is still crashing here in the coming days then I will update it soon.

[Maikoli]

OH! Yeah, right, there is a non-beta version of Millennium, sure, that makes sense!
Thanks for clarifying!

In any case thanks for your work my dude! And good luck on finding the bugs.

All Info I can give you is; that for me when using the beta version of Millennium I had to have the newest version of Extendium for the puzzle icon to show up, but both, 2.0.0 AND 2.0.3 work, just without the icon, meaning the browser add-ons still work without the icon. Nothing ever crashed for me. (Using the aur/millennium 3.0.0_beta.24-1 currently)
But I also only used browser add-ons that were in your table and usable, maybe some of those people who experienced crashes simply used non compatible add-ons? (This behavior is consistent at least since beta.18 btw.)

[redeven]

Millennium: v3.0.0-beta.24
Extendium: v2.0.3
Only line in plugin logs is:

07:51:36.169 Extendium loaded in Millennium version: v3.0.0-beta.24

Observed behavior:

• There is no button for extensions on the URL bar.
• Attempting to launch the extension manager with steam://extendium/manager makes the Steam client become this: