[tex-eplain] Manual eplain.pdf

[Suresh Govindachar]

Hello,

The manual eplain.pdf
(http://www.tex.ac.uk/CTAN/macros/eplain/doc/eplain/doc/eplain.pdf) has a
nice bookmarks-tree.  

1) What has caused this bookmarks-tree to appear?  

2) Although the manual's notice says "Most of this manual is in the public
domain, ...", I have not been able to find the source for the manual --
where is it?

My current interest in the bookmarks tree is to create a bookmarks tree for
presentations made using the plain TeX "package" present.

Thanks,

--Suresh