Rust variables questions

I've been looking for rust variables/commands. There are a few that I don't know what are they for.

Code:

server.entityrate
server.cycletime
server.queriespersecond
server.ipqueriespermin
server.planttick
server.updatebatch
server.netcache
server.compression
time.fixeddelta
time.maxdelta

 

this ^^