=== Essential Reddit functionality that doesn't work with LibreJS 6.0.5 enabled (as of 11/2014) There may be more, this is just from a preliminary look.
The majority of the scripts necessary for Reddit to function properly for the average user are, fortunately, free software. However, not all files are labelled as such. Additional efforts are also needed to ensure that LibreJS recognizes the distributed files as free.
Below, "source file" refers to the unminified source code in the Reddit repository.
Similar to above; ordered concatenation and subsequent minification:
This is not comprehensive, but would be an excellent start.
The blog is a particular concern---it uses a great deal of JavaScript, but seems to work fine without JavaScript enabled.
This simple shell/sed script can be used to add the license header to all source files in one go, assuming that such a header is contained within the file license_header:
$ sed -i '
1{
r ./license_header
h;d
}
2{H;g}' r2/r2/public/static/js/*.js