It is okay. It does not work well, but it does work. Using this on webpages, that use even a small bit of complex CSS (like bosworthtoller), makes this throw up webpage spaghetti. Misaligned text and shapes, icons don't scale correctly sometimes—but it does keep the general shape of the page. Be ready to edit the SVG often, so use this, only if you want to put a little work into it.

Works great. Enables you to save a portion (or the visible region) of a webpage to SVG. Renders the visible elements into SVG fairly accurately. Obviously, since it has to convert what Gecko renders to an equivalent in SVG, it is not always 100% match (e.g. shadows are problematic, CSS blur does not work at all). But that is understandable, the capabilities of CSS and those of SVG are not 1:1, each can do a bit different things visually and matching them 1:1 is probably pretty hard, I can imagine.
BTW, the text parts of the page are kept as text so the screenshots can be manupulated, e.g., in Inkscape as needed. So good job, Mr. Becker; compared to what I've seen and tested in this category of add-ons, this is the best one I found by far.

Doesn't properly render a local file that I tested. Additionally, whether the viewport option captures the entire page or merely the visible portion isn't evident.

Deine Addon, ist die BEEESSSSEER Herr Becker
I`m worried about the permissions :c

not working on https://mindmapp.cedoor.dev/app

the text in nodes dissappear

I liked the add-on, but valued it 4 stars because it captures only the visible part of a page. If you mend it to take a shot of the whole page including areas which can be reached by scrolling, then I make it 5 stars.