I posted lsblk -f already (and findmnt / in the OP).
btrfs subvolume list /
ID 258 gen 361244 top level 5 path @cache
ID 259 gen 361634 top level 5 path @log
ID 424 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-09-16_21-24-30/@
ID 425 gen 308759 top level 5 path timeshift-btrfs/snapshots/2022-09-16_21-24-30/@home
ID 426 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-09-27_13-42-49/@
ID 427 gen 324853 top level 5 path timeshift-btrfs/snapshots/2022-09-27_13-42-49/@home
ID 428 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-09-27_18-45-41/@
ID 429 gen 325443 top level 5 path timeshift-btrfs/snapshots/2022-09-27_18-45-41/@home
ID 430 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-01_22-54-26/@
ID 431 gen 331811 top level 5 path timeshift-btrfs/snapshots/2022-10-01_22-54-26/@home
ID 432 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-01_22-54-36/@
ID 433 gen 331815 top level 5 path timeshift-btrfs/snapshots/2022-10-01_22-54-36/@home
ID 434 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-09-10/@
ID 435 gen 338030 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-09-10/@home
ID 436 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-12-52/@
ID 437 gen 338040 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-12-52/@home
ID 438 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-22-32/@
ID 439 gen 338062 top level 5 path timeshift-btrfs/snapshots/2022-10-06_20-22-32/@home
ID 440 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-10_21-21-55/@
ID 441 gen 343960 top level 5 path timeshift-btrfs/snapshots/2022-10-10_21-21-55/@home
ID 442 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-11_20-13-42/@
ID 443 gen 345349 top level 5 path timeshift-btrfs/snapshots/2022-10-11_20-13-42/@home
ID 444 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-11_20-14-24/@
ID 445 gen 345354 top level 5 path timeshift-btrfs/snapshots/2022-10-11_20-14-24/@home
ID 446 gen 361632 top level 5 path timeshift-btrfs/snapshots/2022-10-15_23-44-29/@
ID 447 gen 357910 top level 5 path timeshift-btrfs/snapshots/2022-10-15_23-44-29/@home
ID 452 gen 359257 top level 5 path timeshift-btrfs/snapshots/2022-10-19_07-30-18/@home
ID 453 gen 359253 top level 5 path timeshift-btrfs/snapshots/2022-10-19_07-30-18/@
ID 454 gen 361634 top level 5 path @home
ID 455 gen 359253 top level 5 path @
And…
btrfs subvolume get-default /
ID 5 (FS_TREE)