Professional photographers often use sequential numbering (001, 002) for raw video files from concerts or airport appearances.
If you received this file from an untrusted source, be aware that generic filenames like "Yeji-001.mp4" are sometimes used to disguise or adware . Yeji-001.mp4
Likely a high-definition (HD) performance clip, a "bubble" (private message app) video leak, or an Instagram story archive. or an Instagram story archive.