While "mmm (143).mp4" isn't a single universal "feature," here is the context typically surrounding files with this specific naming style:
If you found this file on your device or a shared drive, it is likely a or a resource file from a video editing app. mmm (143).mp4
: In digital slang, "143" is a classic code for "I Love You" (based on the number of letters in each word). This suggests the video is likely a romantic edit, a "sweet" moment, or a "soft" aesthetic clip. While "mmm (143)
Are you trying to or determine how it got onto your device ? a "sweet" moment