yup! its an older version of portal that is often more stable than the current steam version and allows easier edge glitching/save glitching among other small changes.
it is recommended you use the source unpack version of the game if you want to run portal
I was running on the steam version for a while because I didn't know that the source unpack version existed or how it worked. I did fine using that but once I started using source unpack a lot of the different glitches and things became more consistent.
It was recently discovered that it is possible to set your mouse sensitivity to a value so high that the game considers it infinite, leading to several new glitchy techniques being discovered.
The rules have now been amended to ban these new techniques in both Inbounds No SLA Legacy and Glitchless.
