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!
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), 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.