XnView Software

it's 500 file formats in reading About>Formats
XnView software downloads in general only include some of the more popular plug-ins, additional plug-ins to support reading, and in some cases also writing, other formats being available for download separately.

However, now that some XnView ...

I downloaded the versions to https://download.xnview.com/XnViewMP-linux-x64.deb for Linux, after starting the program I do not have 500 plugins. Why do not you have so many plugins after installation?