XML - XSLT own application

Is there some documentation I could find, as to how is an XSLT applied
to an XML.

WITHOUT USING tools like cocoon etc.

How do browsers handle it, how do other tools handle it...

Consider I have to make my own implementation of the same, who would I
go about it. Some guidelines...

I'm not sure if my question is clear...

Thanks in advance.
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Regards,
Varun Mehta