pad_kerning.py

font = Glyphs.font

glyph_id_to_name = {g.id: g.name for g in font.glyphs}

# Find all kerns in the source file
seen = set()
for master_kerns in font.kerning:
	for first in master_kerns.keys():
		for second in master_kerns[first].keys():
			first = glyph_id_to_name.get(first, first)
			second = glyph_id_to_name.get(second, second)
			seen.add((first, second))

print(len(seen))
# Add missing kerns to each master
for master in font.masters:
	for first, second in seen:
		try:
			kern = font.kerningForPair(master.id, first, second)
			if kern == None:
				font.setKerningForPair(master.id, first, second, -1)
		except:
			all
print("Done")