For informal communication with (some of) the LAMMPS developers you may ask to join the LAMMPS developers on Slack at https://lammps.slack.com
This slack work space is by invitation only. Thus for access, please send an e-mail to "slack at lammps.org", and explain what part of LAMMPS you are working on. If you just want to contact the LAMMPS developers, please send an email "developers at lammps.org".
Also note that the slack channel is only for discussions related to LAMMPS development, *not* for people looking for help with compiling, installing, or using LAMMPS. For those purposes, please post a message to the LAMMPS forum on MatSci.org. More info about the forum is here.