[Advaita-l] Who is this Angustha Parimana Purusha?

[Venkata sriram P]

नमस्ते प्रवीण महोदय !

I don't know about malayalam work but सीतोपनिषद् doesn't mention 
anything about this.  

There is a mention of the abode of Yoga Shakti to be the 
दक्षिणवक्षस्थल​ of Bhagavan in the form of "srIvatsa"

इच्छाशक्तिस्त्रिविधा प्रलयावस्थायां विश्रमणार्थं भगवतो दक्षिणवक्षःस्थले 
श्रीवत्साकृतिर्भूत्वा विश्राम्यतीति सा योगशक्तिः

सस्नेहं,
श्रीराम