in theme/plugins/asfgenid.py [0:0]
def unique(tag_id, ids):
while tag_id in ids or not tag_id:
m = IDCOUNT_RE.match(tag_id)
print(f'WARNING: id="{tag_id}" is a duplicate')
if m:
tag_id = '%s_%d' % (m.group(1), int(m.group(2)) + 1)
else:
tag_id = '%s_%d' % (tag_id, 1)
ids.add(tag_id)
return tag_id