An "IdeaPad 3 CB 11IGLO5" apparently, likely from mid 2020. And it's just vanilla Mint + XFCE, I haven't done anything to optimize it. It ain't fast, but it is definitely fast enough for normal web / writing / etc, and 4GB of ram goes a lot further than I expected (with Firefox and a few dozen tabs, I'm at around 2GB used, and I almost never touch even 3GB).

My only real complaint is the pretty crappy screen, it's one of those cheap LCDs that drastically changes color/contrast/etc as you move away from the tiny perfect viewing angle... but that screen is probably a moderate amount of the reason why the battery lasts so long.

When fully charged and on low brightness, Mint claims I have ~77h of battery life. It's definitely over-estimating, but 30 is totally reachable while I'm doing my normal stuff (likely not on high brightness tho). And when closed I lose like 2%/week, noticeably better than any other laptop I've ever had.