Gagga is the first letter of the word Gurmukhi itself, and of Guru, Granth and Gurdwara, which places it at the head of a great deal of Sikh writing and inscription. That frequency has a practical consequence for anyone reading manuscripts, because a letter that appears constantly is a letter whose hand is most easily characterised: palaeographers comparing Gurmukhi manuscripts look at high frequency forms first, since the way a particular scribe turns a common stroke is a steadier signal than the way the same scribe writes a rare one. The name of the script is itself the subject of the standing argument about its origin. Gurmukhi is read within the tradition as meaning from the mouth of the Guru, and Sikh reference works credit Guru Angad, the second Guru, with giving the script its settled form in the sixteenth century.
Historians of Indic writing hold that the letterforms were already in use in the mercantile Landa hands of the Punjab, descended through Sharada from the Brahmi line, and that what the Guru did was to order, name, fix and dignify an existing repertoire rather than to invent one. The atlas records both positions and settles neither. The disagreement is also worth stating in its mildest form, since neither side denies the other much. Nobody argues that the Gurus drew the letters from nothing, and nobody argues that the painti as an ordered, named, taught set existed before them; what is at issue is how much of the work was invention and how much was arrangement.