GitLab supports defining custom Git attributes such as what files to treat as binary, and what language to use for syntax highlighting diffs.
To define these attributes, create a file called .gitattributes in the root
directory of your repository and push it to the default branch of your project.
The .gitattributes file must be encoded in UTF-8 and must not contain a
Byte Order Mark. If a different encoding is used, the file's contents will be
ignored.
The .gitattributes file can be used to define which language to use when
syntax highlighting files and diffs. See "Syntax
Highlighting" for more information.