I assume m- is multisig, not sure abut the others.
After seeing
this topic (which points to
transaction 1 and
transaction 2), I am now curious what the difference is. This looks like someone with mining-access playing around (1 sat/vbyte and 0 sat/vbyte), but I don't know why.
Somebody needs to email blockchair support, preferably without using a Proton or tutanota email addresses as Blockchair is using Yandex (who's filtering those mail servers) as their email service, and ask them what these prefixes are supposed to mean or if they are just for internal use. There is no trace of these addresses in their Github docs:
https://github.com/Blockchair/Blockchair.Support