[kej]

Presumably something like this is what's happening in /r/A858DE45F56D9BC9/

[mdadm]

Possibly. Searching up some of the content on there revealed this[0], so at least some of it is (most likely) data.

[0] http://a858.soulsphere.org/

Edit:[1] shows that this is most likely a false-positive.

[1] https://www.reddit.com/r/Solving_A858/comments/24vml1/mime_t...