I have many .olk14MsgSource and .olk14MsgAttach files taking up space - can I delete without repercussions?

My Google drive is almost full and when I went to delete large files, I have many of these two types of files: .olk14MsgSource and .olk14MsgAttach

They are large 6-25 MB each. Can I delete them without repercussions?

What are they?

Do I need them?

Where are they stored on my hard drive? (I only found them because of my Google drive showing me the large files)

Please help!