fDebug flag can be used for that like:

It's initialized according to -debug setting:

Ideally it should be applied to log messages that doesn't hold information for a sysadmin, but mainly for developers, like: https://github.com/lbryio/lbrycrd/blob/master/src/claimtrie.cpp#L1927

To be updated with more examples where it should be applied after #137 gets merged as it adds more cases.