Viewing/sharing existing per-site (“cosmetic”) CSS rules? (re-ask)

[gojomo]

STILL WONDERING (previously unanswered: VIewing/sharing existing per-site ("cosmetic") CSS rules?)

I successfully used [ Brave → Block Element Via Selector ] to block an annoying site design element. Now, I’d like to advise someone else, less versed in the ways of the DOM/CSS how to do exactly the same block rule.

Is there anyplace I can view the rule I set up?

Any way to share it as text for precise duplication?

[gojomo]

As additional detail, I’m trying to block the infernal Twitter.com search/what’s-happening right-column. I had a rule that worked, now it’s not working.

It looks like a rule for div[data-testid="sidebarColumn"] should work, and adding that via right-click Brave->Block Element via Selector causes it to disappear, momentarily, but it reappears after a tab/URL reload.