Skanda Purana — Mahesvara Khanda, Shloka 156
ते तृप्तास्तर्पयन्त्यस्य पूर्वजान्यत्र संस्थितान् । एवं स्वानां चोपतिष्ठेच्छ्राद्धं यच्छंति ते वरान्
te tṛptāstarpayantyasya pūrvajānyatra saṃsthitān | evaṃ svānāṃ copatiṣṭhecchrāddhaṃ yacchaṃti te varān
当他们得以满足时，也会反过来使此人的祖先——各安住于其所属境界者——得以饱足。故应如法为自家族系奉行施食祭祖之Śrāddha；于是祖灵便赐予福愿。
Mahākāla
Listener: a king
Scene: A layered ancestral chain: the performer’s offering rises to satisfied pitṛs, who then send nourishment further back to earlier forebears; finally blessings descend as light upon the family, symbolizing boons granted.
FAQs
Śrāddha works through a chain of satisfaction: higher Pitṛs become pleased and nourish earlier ancestors, culminating in blessings for the performer.
No site is specified; the emphasis is on the ritual’s intergenerational efficacy.
One should perform Śrāddha for one’s own ancestral line, with tarpaṇa (satiating offerings) as the operative principle.