How to run userscripts on chrome-extension pages?

[BGM]

Is there any way to run a userscript on a chrome-extension:// url?

I want to make some tweaks to the Feedbro extension, but Tampermonkey won't run on chrome extension pages.

Is there a way to do it?  I don't have to use Tampermonkey.

[Deozaan]

Does this one do the trick?

Violentmonkey provides userscripts support for browsers:
https://violentmonkey.github.io

I have no experience with this, but saw it mentioned recently on the forum. Sorry in advance if it's not helpful.

[BGM]

No, the problem is that the userscripts, doesn't matter what "monkey" you use, don't support affecting extensions - they say it's a security risk.

So I'm looking for another way short of modifying the extension itself.