The µvMac emulator allows modern computers to run software made for early Macintosh computers, the computers that Apple sold from 1984 to 1996 based upon Motorola's 680x0 microprocessors, most notably the Macintosh Plus.
µvMac is maintained by InvisibleUp.
µvMac began in 2020 as a spin off of the program Mini vMac. Mini vMac, while great, was inflexible and very difficult to maintain. This fork was created to clean up and modernize the code base, make the project easier to compile and hack on, and allow for much easier user configuration. The intent of Mini vMac was to create a "emulator collection" of many very optimized "variations" of the same codebase. I consider this much more trouble than it's worth, and intend to focus more on maintainability and accuracy.
The “micro” in the name refers more to the side and simplicity of the codebase than of any particular binary. That said, having every possible system emulated by one single program would, in fact, be smaller. Also it was meant to imply that this comes "after" Mini vMac.
Besides the Macintosh Plus, there are also emulations of the Macintosh 128K, 512K, 512Ke, SE, Classic, and SE FDHD. Work is in progress on Macintosh II emulation, which seems to be mostly stable from what testing I've done.