This no longer works in v19.10.48:
option //RegularExpressions=Perl
> 201234567890_backup.dat
dir "::^20\d{10,10}.*\.dat$" : => no results
It used to work in v19.10.46.
option //RegularExpressions=Perl
> 201234567890_backup.dat
dir "::^20\d{10,10}.*\.dat$" : => no results
It used to work in v19.10.46.
