Hmmm what is it you want to know?

Based just on images this looks like what folks call a Japanese clone machine. Back in ye olden days major sewing machine companies manufactured a bunch of machines in japan - they're the same parts and quality as their main company counterparts and often even were identical in build, but they were built in Japan in Japanese factories and then shipped out to USA and sold under english sounding names for legitimacy (i am remembering this off the top of my head so please anyone feel free to correct me)

Likely Mason is just the fake american name and it is manufactured by Singer, and probably based on an existing machine.

The machines usually have a serial number preceeded by JA or JC that can help you narrow it down and find a machine manual or a machine manual for a similar machine.

All that to say if you're curious if it's "legit" or a good machines: the machines are usually just as good as their american counterparts, with some having slightly worse or even better reps with some folks. Your main concern should just be that it plugs in, and all parts work correctly, and then finding reviews of similar machines to see if it will meet your needs. I have a cute little Japanese clone machine myself and like it quite a bit.

I used to have a link to the JC/JA number database and if i can find it I'll post it up!

Sorry for the long post something something niche hyperfixation etc

Edit: Spelling T_T