This folder contains the files necessary for the math4 theme.  These files are
tracked by git and any changes made to them will be overwritten when you 
upgrade.  The two exceptions are math4-overrides.css and math4-overrides.js.  

These files do not need to be present, but if they are they will be included 
in system.conf and will override the math4.css and math4.js theme.  They can 
created by copying math4-overrides.css.dist and math4-overrides.js.dist.  This 
is similar to how localOverrides.conf interacts with defaults.conf and 
localOverrides.conf.dist.  In particular if you upgrade your server
math4-overrides.js and math4-overrides.css  will not change, but their .dist 
versions and the other math4 theme files may change. This might cause problems 
until you merge the changes. 

If you want to customize math4 you should only change math4-overrides.css and
math4-overrides.js.  Note: Because you can include arbitrary jQuery in 
math4-overrides.js you can actually change pretty much anything, including 
adding new html or changing existing html.