Kashayapahuda (कषायपहुड / कषायप्राभृत) is considered, in the Digambar tradition, to be based on the 12th Ang of the Gandhars – “Drashtivāda (दृष्टिवाद)”.

So, in short:

• There were 12 Angas preached by Bhagwan Mahavir and compiled by his Gandhars.
• The 12th Ang is Drashtivāda.
• Kashayapahuda is accepted as a text derived from / based on this 12th Ang (Drashtivāda), especially its portion dealing with kashāyas (passions).

Shwetambar tradition does not accept Kashayapahuda as an Agamic text, but Digambars highly revere it as preserving part of the lost Drashtivāda.