Warning, the reaction to massive security issues in a bundled PDF reader of the file manager made me uninstall all of these apps. Safety of my device and data is paramount.

https://github.com/SimpleMobileTools/Simple-File-Manager/iss...

https://github.com/SimpleMobileTools/Simple-File-Manager/iss... where the developer shows no grasp of security "what can happen to an app without internet access?"

A "simple" file manager should not come with a PDF reader.