Definitely min-pin mix. The mother's owner bothered to dock the tail (very few breeds are actually born stubby and docking has to be done in first week unless you got cash to pay for tail amputation later)
Maybe some Dash or Chi for the shorter legs/longer back?
Is it the camera? The dog looks liver. Such a deep dark liver color is not in minpins (that is a deep liver.. the eyerims look brown, nose is deep black brown and nails are dark tan. Pure min pins are either self red or Black & tan. Unless "designer" mix muttlies.
Flyers posted in local area on fences, in stores are best way to ask owner.. also look for lost fliers.
Was the owner ever found?
I remember when my son's service dog.. a fat min pin papered as Ernst Borgnine..aka Fatty, got loose while the respite provider was watching my son. He was already deeply dependent on the dog. His chip that I had paperwork for did not show but the finders and I put fliers everywhere until the ones I left at 5 mile mark found him. Luckily he and his sister also had a tattoo in hind . Plus he was pretty unique looking with very bad ear cut.
example of two dif min pin body types from same litter . I used to not like minpins til we were lined up with Fatty.
This is the two minpins with my huge retired 17 yr old cameo persian show cat. Debil is 8 lbs and fatty was 27lb never lost more after reaching 15lb
Fatty hanging with his boy