You can discuss general iPXE topics using GitHub discussions. If you believe you have found a bug in iPXE, then you can raise an issue.
For a more direct interaction, you can also try talking to the iPXE developers using Matrix or IRC.
You can contact the iPXE developers by sending e-mail to ipxe-devel@lists.ipxe.org. You can also subscribe to the mailing list, or view the archive of past messages.
To talk to iPXE developers in real time, you can join the #ipxe
channel on the Libera.Chat IRC network or the #ipxe:matrix.org
Matrix room.
For commercial enquiries, such as custom development or business-critical support issues, please contact vendor-support@ipxe.org.