– Pali diacritics. You can copy and paste these letters when you need them for searches:
ā ī ū ṅ ṃ ñ ṭ ḍ ṇ ḷ Ā Ī Ū Ṅ Ṃ Ñ Ṭ Ḍ Ṇ Ḷ