Any reference work files things under headings, and a heading imposes a shape. Where the shape does not fit, the honest course is to say so on the entry rather than quietly bend the subject, so the decisions taken here are set out.
It is not filed under the Abrahamic entry. The atlas holds a single entry for the God of Judaism, Christianity and Islam, on the ground that all three trace their worship to the God of Abraham. Sikhi does not. It arose in fifteenth-century Punjab, in conversation with Indian devotional religion and with Islam as a neighbour, and it reached its monotheism by its own route. Whether the Sikh and the Abrahamic conceptions have the same object is a real question and a contested one, and this atlas has no standing to settle it; the atlas deliberately asserts no identity in either direction.
No polarity and no archetype are assigned. The atlas normally tags a deity Yang or Yin and gives it a Jungian archetype. Both are Western esoteric overlays that this atlas imposes on its subjects, and neither is attested anywhere in Sikh thought. Yang in particular is defined here as the active, projective, "traditionally masculine" charge, and applying it here would contradict the tradition's own teaching. Both are left unset on purpose, as they are on the Abrahamic entry.
Gender is recorded as beyond gender, and that is a claim, not an evasion. Punjabi grammar and much of the scriptural language are masculine, and English translations have made God "He" for a century and a half. But God is nirankar, without form, and ajuni, not born, and neither admits a sexed body; and the Guru Granth Sahib addresses God as father and as mother, and uses at length the image of the human soul as a bride longing for her divine spouse. Nikky-Guninder Kaur Singh's study of that imagery is the authority cited for the property. Recording the grammar as the theology would have been the easier error.
No identification with any other deity is asserted. Not with the Hindu conceptions whose vocabulary the Gurus shared, not with Om (Sikh theology distinguishes Ik Onkar from the Hindu Om, and the identification is contested, which is why the atlas does not link the mantra Om to Sikhism either), and not with any figure in any pantheon. Sikhi is not a syncretism of Hinduism and Islam, a nineteenth-century characterisation Sikh scholarship has rejected at length, and this entry does not reintroduce it through the back door of a stray cross reference.