Hi! I’ve been trying to create an extension that deals with navigation but I’m getting an Uncaught (in promise) Error: Illegal URL: about:* for any action with these pages. Can anyone help me with this?
Well, I’m afraid I have only bad news.
Extensions can “work with” only with “about:blank”, everything else is blocked.
There is a plan to add support, but I wouldn’t hold my breath 
Is there any ways to atleast set active on their tabs? Nothing seems to be working for them. Thank you for the response too!
If tab with “id” 79 is “about:addons”, then these operations will work fine:
await browser.tabs.update(79, {active: true})
await browser.tabs.update(79, {url: 'about:blank'})
Maybe post here what exactly are you trying to do?
I’m trying to create a custom tab view. Yes, this is working fine. I’m planning to add a URL bar to my extension, is there any way to allow for visiting the about:* pages from it?
None that I am aware of. As @juraj.masiar said, only about:blank can be accessed by an extension. See this note about the url property on the tabs.create() options object for more information.