I just noticed that DTTG does not display files in SVG format (I’m using the latest version 2.6.3 on iOS 11.4.1). The preview pane is just blank. I can display the graphic by using “Open in” and then “Preview”, but obviously this is only a workaround. Would be nice if DTTG supports this (and maybe other vector formats) directly.
BTW: Is there a list available with all the supported file formats?