The current description of AuthoritySeparator is 
'Separate multiple displayed authors, series or subjects with'

But it is not used to separate multiple authors, series or subjects, it is used to separate the main entry and its subdivisions for subjects and contributors only. Not authors nor series.

It should also be specified that it is used only in non-XSLT views.

To test:
1. Change the value in AuthoritySeparator for something crazy (ex. -a-a- )
2. Change the value of OPACXSLTDetailsDisplay to empty
3. Add or modify a record and enter 
- an author in 1XX (with multiple subfields)
- several series in 440 (with multiple subfields each)
- several contributors in 7XX (with multiple subfields each)
- several subject headings in 6XX (with multiple subfields each)
4. Add the record to the cart
5. Open the cart and click on 'More details'
6. Note that only subjects use your crazy separator and not in between each subject but between main headings and subdivisions.
7. Open the record in the OPAC
8. Note that only subjects and contributors use your crazy separator, again not in between each entry but between main entries and subfields.

It seems to be used differently across modules. I think that should be a discussion, but right now, I suggest we change the description to 
'Separate main entry and subdivisions with ___ (non-XSLT view only)'.