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. Simple one-line problems are likely to receive an answer for free. For anything more complicated, you can book an initial 30 minute online consultation to discuss your problem and test out some possible solutions.
For more complex problems, or for custom new feature development, you will be provided with a proposal document describing the work to be carried out, the acceptance criteria, and a fixed price for the work (regardless of time taken). The price of your initial 30 minute consultation will be deducted from the overall cost of the project.