These files potentially obtain a new filename during migration between 3 to 4 (if executed by the runtime itself)
If there is already a file at that location then the OLD file is prefixed with obstructed and the file that should be there in the new situation is given the name of the old file.
This will result in a warning in your server log by the way.
I'm not sure how this can occur, perhaps (some part of) the migration was done manually or twice?
If the files are exactly the same then it will be fine to remove the obstructed ones.