The _source suffix typically indicates that this is the original, highest-quality version of the upload stored on a server, often found when inspecting a web page's source code or using a media downloader.
Without more context on where you encountered this specific ID, it remains a for a piece of user-generated content. 0h2umg10y40m3b0khb3q8_source.mp4
While this specific string doesn't represent a known public viral video or historical event, The _source suffix typically indicates that this is