Indeed it did - the "
modern@themes.mozilla.org.xpi" XPI file was just sitting there in the extensions folder, looking all installable (the RDF
etc looked like they should), but I thought I would ask before installing it - you mentioned a "add-on database" being possibly corrupted...
But, yes, straight "Install from file" worked great, with the usual "your old theme is disabled, your new theme will take over when you restart" messages.
Cool, back to the "all gray, all the time" look instead of the "too much white with occasional splotches of color" look.
Thanks, f-r.
EDIT: And thanks also, therube - I fixed this as my post describes, then saw your reply. I am not making this up - my old "Modern" theme disappeared from the list of installed themes, I was forcibly switched over to "Default", and I had done
nothing with themes at all. I do full uninstalls of SM for every new build I see from Bill, and then fresh installs with those... with my profile, of course, going along for the ride.