Odd ._sync files in sync client

Hi nextcloud guys,
I have installed Nextcloud on Ubuntu via snap (for an POC) and when I’m using the Windows 10 sync client (2.5.2) and I activate in windows the setting to see hidden files, I can now see the sqlite db files which I’m also able to delete…

._sync_XXXXXXXXXXXX.db
._sync_XXXXXXXXXXXX.db-shm
._sync_XXXXXXXXXXXX.db-wal

How good/bad is this? Not techi guys could delete them and maybe break something?

Thanks!