thanks for the PSA, I use the network tab alot and was still unaware. If you hover in the field the '?' symbol will actually link to this help page.
when you filter the requests and export an .har, the archive will include only the requests listed. For adhoc extraction I then poke at the har with jq to get what I need.
TIL HAR files are just JSON, I always assumed they were some kind of binary archive file. Very convenient.