If your organization, school, or company has volume licensing for FileMaker Pro and want to make your package Munki-able, this is how you do it (based on Assisted install for FileMaker Pro and FileMaker Pro Advanced).
Older: Find your FileMaker installer .mpkg file. This installer file will likely come on a read-only medium (read-only .dmg or actual physical CD/DVD), so drag it to a temporary read/write location (e.g., your desktop).
Newer: In newer versions, the .dmg will have the Assisted Install.txt right in there next to the .pkg, and there is no .mkpg. If you are copying to a working folder (e.g., on your desktop), be sure you're copying all the invisible files as well.
Both Older and Newer: Add in or change an options as you see fit (you don't need quotation marks around anything—just put the text for AI_USERNAME, AI_ORGANIZATION, and AI_LICENSEKEY after the equal sign on each line). For other options, 0 means No and 1 means Yes.
Make sure you change AI_LICENSE_ACCEPTED and AI_SKIPDIALOG to be 1 instead of 0.
When you're done, close and save the file.
Older: Next, just go ahead and import that modified .mpkg file into Munki (e.g., munkiimport FileMaker Pro ## Advanced.mpkg). The Munki import process will create a read-only .dmg container for the .mpkg file.
Newer: For newer versions, there is no .mpkg, so you'll have to create a disk image of the working folder you created earlier (e.g., ~/Desktop/FileMaker). Be sure to make it an HFS+ disk image and not an APFS one.
You can then munkiimport the resulting .dmg.
Make an installs array (/usr/local/munki/makepkginfo -f) based off the installed FileMaker so Munki doesn't get into an install loop, and then paste that installs array in the pkginfo for FileMaker and run makecatalogs afterwards.