That is (or was) the real member names when it was compiled.
The problem is this particular code was obfuscated before it was compiled. As such, the original source code names are unrecoverable without an additional mapping.
Programmers may deliberately obfuscate code to conceal its purpose (security through obscurity) or its logic, in order to prevent tampering, [and] deter reverse engineering ..
In this case, a manual mapping can even be applied: "2YKe...Sxe0" means "attributes", as evidence by the assignment from a [named] parameter. But this manual reversal is very tiresome, e.g. what is the purposeful name of the class?