Tells the server to ignore numbers in JavaScript and CSS file names (e.g. main.20150101.css), but the browser will still interpret it as a new file whenever the number is updated.

cachebuster

# cache-busting via file name
# Filename example:
# <link rel="stylesheet" href="/css/main.20150310.css">
# h/t Jeremy Keith (https://adactio.com/journal/8504)

RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.).(d).(js|css)$ $1.$3 [L]