Welp, it appears the battery on my 2019 #Apple #MacBook is giving up the ghost, & the Apple Store tells me Apple won't source a replacement for a box this old. (Because of course not.)
Far as I know the box is still useableāas long as it's tethered to the wall.
A new one wouldn't be unmanageably expensive, but <weary sigh>
(Yes, yes, I know, #Linux, but that's not a straightforward conversion. I'm already exploring that option.) 1/2