When mod_php installs, it creates /etc/apache2/conf/modules.d/70_mod_php.conf. It correctly adds .php .php3 .php4 files as x-httpd-php. However, it does not add the type for x-httpd-php-source, .phps. 70_mod_php.conf should have a line like: AddType application/x-httpd-php-source .phps added to it for .phps files to work. I have added such a line to my config, and .phps files work. (.phps files allow developers to share the source of a php file with other devels, by causing mod_php to outpu syntax-colored php code, instead of interpreting it as it normally does)
Thanks for the tip... Committed.