Hidden files and directories (those whose names start with a dot .) should most, if not all, of the time be secured. For example: .htaccess, .htpasswd, .git, .hg…
RewriteCond %{SCRIPT_FILENAME} -d [OR]
RewriteCond %{SCRIPT_FILENAME} -f
RewriteRule "(^|/)\." - [F]
Alternatively, you can just raise a “Not Found” error, giving the attacker no clue:
RedirectMatch 404 /\..*$