From Stefan Matthias Aust's website (https://www.3plus4.de/scala/):
* How to use it
The Vim editor (https://www.vim.org/) can be customized using the
following two resources located either in your home directory or
in some system-specific directory:
    .vimrc  is the main configuration file; it should at least
            contain the command "syn on" to enable syntax
            hightlighting
    .vim    is the Vim configuration directory; it contains scripts
            (https://www.vim.org/scripts/) in predefined locations.
            The support files for Scala are contained in the three
            directories "indent", "syntax" and "ftdetect"; simply
            copy them to your Vim configuration directory.
Vim searchs for user-specific resources at the following locations:
    - under Linux, Solaris, etc. usually /home/<username>/.vimrc
    - under Mac OS X: /Users/<username>/.vimrc
    - under Windows:  %HOMEDRIVE%%HOMEPATH%\_vimrc
* Thanks
scala.vim was contributed by Stefan Matthias Aust (nobody@3plus4.de)