I just realized that no commonly used vector graphics file format is supported to upload files. Neither .svg nor .eps can be uploaded. Why is this? Especially for .svg, it should be fairly easy to include the picture within the text of a post, but even attaching it to share a logo or something else would be sufficient. I hope this can be changed.
The problem with SVG images specifically is that they can include executable code, which you have to scrub. Mediawiki does this, but it's not that easy. Embedding SVGs from your own server works fine already though: In the BBCode editor, use [ IMG ] https://....svg [ / IMG ] (without spaces). In the Rich Text Editor, click Image and enter the URL.