Adding SVG

Hi there. Can you please explain how to add the svg file type by going into Setttings
then
Mime Type Settings
and inserting and saving whatever exact text needs to be saved in the “Add Values” window?

In your Media Types reference spreadsheet, I only see svg+xml under the Name column and nothing under the Template column. I assume what I would enter in under Add Values is “svg+xml = (then whatever is in template column)”, but there is nothing there. My svg files have vanished off of my site, and I am looking to make them reappear.