wal recalls me something.
It may be or not related, but I found in my macOS Library/ folder files:
NoteStore.sqlite-wal --> Group Containers/group.com.apple.note
NotesV6.storedata-wal --> Group Containers/group.com.apple.note
places.sqlite-wal --> Firefox folder
ABAssistantChangelog.aclcddb-wal --> AddressBook
and some others.
The file contents holds a mix of binary data and text data.
HTH