Hello! It's PCAD. Follow these steps to import into Altium:
Select File > Import Wizard.
Select PCAD library from the list and click Next.
Click Next again to skip importing a design.
The next dialog will be to import a PCAD library. Add the file downloaded from SnapEDA and follow the rest of the prompts.
Let us know how it goes!
Answered 2 years, 2 months ago.