Rishi: As per Vājasaneyin anukramaṇī for VS 19.64 (Pitṛ/Agni-kavyavāhana stratum; verify in your critical apparatus).
Devata: Agni (Kavyavāhana)
Chandas: Gāyatrī-like (two pādas of 8 syllables each in RV-style; confirm by scan of the VS recension).
Samhita Patha (Devanagari)यम॑ग्ने कव्यवाहन॒ त्वं चि॒न्मन्य॑से र॒यिम् । तन्नो॑ गी॒र्भिः श्र॒वाय्यं॑ देव॒त्रा प॑नया॒ युज॑म्
Transliterationyám agne kavyavāhana tváṃ cit mányase rayím | tán no gīrbhíḥ śravā́yyaṃ devatrā́ panayā́ yújam
Translationഹേ അഗ്നേ, കാവ്യവാഹനാ! നീ യോജ്യമെന്നു കരുതുന്ന ധനം—അത് ശ്രവണീയമായ (കീർത്തിയുള്ള)തും സുസംയുക്തവുമായതും ആയി, ഞങ്ങളുടെ സ്തുതിഗീതങ്ങളാൽ, ദേവമുഖമായ രീതിയിൽ, കൃപാപൂർവ്വം ഞങ്ങൾക്കായി നേടിക്കൊടുക്കുക.
Padapatha (Word Analysis)यम् । अग्ने । कव्य-वाहन । त्वम् । चित् । मन्यसे । रयिम् । तत् । नः । गीर्भिः । श्रवाय्यम् । देवत्रा । पनया । युजम्
Word by Wordकव्यवाहनO carrier of the oblation to the Fathers/wise (kavya) श्रवाय्यम्worthy to be heard, famed देवत्राamong/with the gods; in the divine sphere पनयाwith skill/admiration; with winning manner युजम्yoked/joined; a yoker/ally (fitly joined) 
Viniyoga (Ritual Application)