There are popular plugins like Modern7z 1.9 (often abbreviated as MM 1.9 or similar in archive names) which add extra compression methods to the 7-Zip program.

While the exact contents depend on where you got the file, "MM_19" is a common shorthand in specific technical fields:

The Official 7-Zip Download is the standard and most reliable tool. For macOS: You can use The Unarchiver or Keka .

Strings like "MM_19" frequently appear in encoded data within SEC EDGAR filings , though these are typically parts of larger text documents rather than standalone downloadable archives.

Are you trying to from this archive, or did you receive it as part of a software installation ?

Since Windows and macOS do not always support .7z files natively, you will need a third-party tool: