My apologies; happy to explain.
2.10 refers to the version of linuxcnc. 2.10 and "master" are the same currently. Also referred to as the development branch, etc.
RIP is a run-in-place version of linuxcnc. A package install (commonly installed via synaptic package manager) contains a nice and easy way for a user to install a pre-compiled package of linuxcnc and all of its dependencies. A RIP "installation" allows the user to compile the project themselves after satisfying all of the build dependencies. It is most commonly used by those doing development work as it is tied directly to github and allows for easy updates of code other developers are working on. It also allows us to compile the changed files quickly to test the work.
If your synaptic package manager is pointed to the master branch, then you don't need to do anything but update (after the buildbot builds the new package)... and enjoy