TIL that:

• tampermonkey has not been open source for years
• many of my userscripts (which typically are JUST injecting css) have been broken due to CSPs preventing the injection of CSS

Using violentmonkey and the "real GM_addStyle" function (rather than a coded-up block to inject a script tag into the document) fixes these issues.

And in particular, it allows 2 of my userscripts to run properly here on my home mastodon server again. yay.

(the zip export from greasemonkey mostly seemed to import into tampermonkey, except a couple of scripts that were so old they were about fixing google+ layout quirks!)