Now, going to admin/reports/tokens, I get the white screen of slumber (not quite death), so I installed Fast Token Browser. However, I am now getting an error at admin/reports/tokens:
ERROR: Argument 1 passed to fast_token_browser_tree_build_content() must be of the type array, string given, called in ... /modules/fast_token_browser/fast_token_browser.theme.inc on line 44
I'll look into this, and maybe file an issue, unless y'all have a quick fix already in mind for this.
From this report in Zulip: https://backdrop.zulipchat.com/#narrow/stream/218635-Backdrop/topic/On.20the.20Mystery.20of.20Tokens