The repository contains the specification (and the proofs) of the Tendermint consensus protocol.
MacTex is Latex distribution for Mac OS. You can download it here.
Popular IDE for Latex-based projects is TexStudio. It can be downloaded here.
In order to compile the latex files (and write bibliography), execute
$ pdflatex paper
$ bibtex paper
$ pdflatex paper
$ pdflatex paper
The generated file is paper.pdf. You can open it with
$ open paper.pdf