No, they are in your /home and system.
- Snapper snapshots are exactly in the hide read-only directory
.snapshotswith root permission by default. - TimeShift snapshots are in the read-write directory
/run/timeshift/backup/timeshift-btrfs/snapshotswhen opening TimeShift to automatically mount this path.
I think they are created in /proc/* by checkpdf process when executed and stored in your RAM like cache, not your disk.
You can delete corrupted PDF files in /home only, that is your decision.
Do not delete files in /proc and /usr!