ʾalif ḵanjariyya is a rare diacritic, is missing on standard keyboards and is sometimes replaced with a fatḥaـَ(-a) in a vocalised Arabic text or omitted altogether, except the Qur'an.
ʾalif ḵanjariyya can be written with or without a fatḥa, e.g. with a fatḥa رَحْمَٰن(raḥmān) in the Middle East or without a fatḥa رَحْمٰن(raḥmān) in South Asia (Pakistan, India and Bangladesh)
The word اللّٰه(allāh, “Allah”) is usually produced automatically by entering "alif + lām + lām + hāʾ" - الله (read from right to left). The word consists of ا(ʾalif) + ligature of doubled ل(lām) with a shaddaـّ and an ʾalif ḵanjariyya above ل(lām).
In Wiktionary we use ʾalif ḵanjariyya to generate a correct transliteration ("ā") and to indicate a long /aː/. A fatḥa alone, without ʾalif ḵanjariyya or a long alif ا(ʾalif) would be transliterated as a short /a/.
