Set icon for file type, Linux Mint

I want the files with the extension **.api** to have some chosen **SVG** icon in the File Manager. Assume, we have a file: /usr/share/icons/HighContrast/scalable/apps/utilities-terminal.svg I add a new MIME type: create a **~/.mime.types** file with a line: **text/x-api api** The question is: how should I link the SVG file name with the MIME type? NOTE: No need of creating the custom icon, no need to launch some application by double-clicking. This question deals only with the linking of the given icon to file extension.