One of the information attributed to the song when it is uploaded is the artist's name.
The artist information depends on ID3 tag or filename ARTIST - Title. When a song from a certain artist is added to the cloud for the first time, the artist is defined and automatically saved and will be used internally to index all the songs associated with it.
If the name of the file format is different from that shown (ARTIST - Title) and no artist is specified by tags, the song will be assigned to UNKNOWN artist.
