I found code on github that is using cfsessionswap tag. It doesn't run on lucee and I can't seem to find it on adobe, is this a newer adobe tag? what does it do?

There is no such tag documented for either Adobe or Lucee. If it was

<cf_sessionSwap>

it's a custom tag

It would be useful if - when asking questions about code - you actually showed us what the code is.

Please don't post the same message in different rooms. You also posted this in #cfml-general as well. Also to echo what Adam has said; if you want people to give you good answers you need to ask good questions. A simple link to the github repo would have been no effort for you is helpful to people trying to help you. :)