Meaning of normal_relaxed, tumor_relaxed, .._stringent (question)

[max-vdL]

Hi,
I was wondering what data exactly we can find in the above mentioned vcf files. My guess is that the normal_relaxed.snv.vcf file contains all snvs that can be found in the normal sample. In the _stringent file more filters have been applied to the _relaxed file, so we will see a subgroup of the snvs from _relaxed.
The same would apply to the tumor_ files.
Is this correct? Because when looking at those files in the a genome browser the mutation frequency seems to be higher in the "_normal" file. So either I mixed something up in my labeling or I understood these files wrong.

Best, Max