What are the default dynamic factorization and renormalization scales in MadEvent?

Since v.4.2.17, there is a new default dynamical scale choice in run_card.dat file:

#*********************************************************************
# Renormalization and factorization scales                           *
#*********************************************************************
 F        = fixed_ren_scale  ! if .true. use fixed ren scale
 F        = fixed_fac_scale  ! if .true. use fixed fac scale
 91.1880  = scale            ! fixed ren scale
 91.1880  = dsqrt_q2fact1    ! fixed fact scale for pdf1
 91.1880  = dsqrt_q2fact2    ! fixed fact scale for pdf2
 1        = scalefact        ! scale factor for event-by-event scales

i.e., variable factorization and renormalization scales,set to the central mT² scale after kT-clustering of the event. For a single heavy particle, this corresponds to the M²+pT², for pair of heavy particles it is the geometric mean of M²+pT² for each particle, for massless particles it is the pT² of the last pair after clustering. If the last clustering is a t-channel colorless exchange (as, e.g., in WBF), the two fact. scales are set to the last mT² values on either side.

These scales are overridden by scales defined in ​setscales.f, if they are returned as non-0.

See How do I implement my own renormalization/factorization scales in MadEvent ? for information about how to implement your own scales in MadEvent.