info break
Does the trick.
trepan2 is a little sparse on documentation. When in doubt, for trepan, as for many gdb inspired command line debuggers start with the assumption it has the same command structure as gdb.
I was initially misled as pdb is a bit of an exception to that assumption and varies from gdb convention more than other command line debuggers.
Obviously trepan doesn't have everything gdb has, but to get e.g. all info "subcommands" type the main command i.e.
info
And then once you find the subcommand you are interested in (e.g. in this case break)
help info break
And finally it is documented, although sparsely:
https://python2-trepan.readthedocs.io/en/latest/commands/info/break.html