CloudBees Jenkins Platform version naming.
How to know which Jenkins / Jenkins LTS version is based on.
Naming differences between Rolling and Fixed version.
The CloudBees Jenkins Platform version is composed by four coordinates in Rolling release and by five in Fixed release. First three means the same in both, referring the Jenkins core version. That Jenkins core usually point to a Jenkins LTS but it can also point to an internal CloudBees build of Jenkins core, which include additional fixes and / or improvements.
If the fourth coordinate is 0 (followed by a fifth one) means that it is a CJP Fixed, in other case it is a CJP Rolling.
The last coordinate (the fourth one in Rolling and the fifth one in Fixed) means CloudBees release number (usually 1).
Thus, 188.8.131.52.2 belongs to CJP 2.7.20 Fixed based on Jenkins core 2.7.20 (CloudBees compilation).
The list of plugins included in the different releases of CJP 2.x can be found in the CJP documentation:
Plugins included in CloudBees Jenkins Platform 2.x
These lists contain the plugin ids, their versions and whether they are required or optional and tagged with suggested (by wizard) and verified (CAP Collection)