FWIW creating a hidden folder on macOS is now a little simpler (I think since 10.13, maybe earlier).
- Press cmd-shift-. to show invisible items
- Create a folder and name it (in this case 'PMIngestIgnore')
- Select the newly created folder and press cmd-i (or right click...Get Info)
- Add a full-stop/period at the beginning of the filename in the 'Name & Extension' section of the Get Info window (in this case '.PMIngestIgnore')
- Close the Get Info window (or press return/enter) then select "Okay" at the "Are you sure..." prompt
- Press cmd-shift-. to re-hide invisible items
Okay, it's still mildly fiddly (but it takes w-a-a-y longer to read these overly explicit instructions than to actually create the hidden folder!
), but at least it doesn't involve using other apps or typing arcane instructions into Terminal etc. - however...
... a checkbox within PM would be far far easier and more discoverable, great suggestion.