FYI According to `man 5 dir_colors` both forms are valid, although the ".extension" form should be considered obsolete.
https://manpages.debian.org/testing/manpages/dir_colors.5.en.html *extension color-sequence Specifies the color used for any file that ends in extension. .extension color-sequence Same as *.extension. Specifies the color used for any file that ends in .extension. Note that the period is included in the extension, which makes it impossible to specify an extension not starting with a period, such as ~ for emacs backup files. This form should be considered obsolete.
