This is a workaround module that supports inserting SVGs inline from CKEditor in Drupal 8. This module should in theory be redundant when https://www.drupal.org/node/1014816 is resolved.
The code is mainly a copy of D8 Editor File upload, which has been updated to insert an img element with its src attributed set to the uploaded SVG file instead.
After saving a post with an inserted SVG, the editor will return to the built-in image widget, where additional formatting and a caption can be added.
- Download and enable the module as usual.
- Go to your filters admin (admin/config/content/formats).
- Edit the format on which you want to enable the insertion of SVGs.
- Drag the 'S' icon to the "Active toolbar".
- Configure the plugin settings in the vertical tabs above the toolbar Save.