Hex Viewer App Features :
1. Opening all files without a corresponding Android application.
2. Display of the file in hexadecimal (or plain text) with the possibility to modify the content (in hexadecimal only).
3. Saving the file on the smartphone/tablet.
4. Search option in the open file (hexadecimal and plain text modes).

(1) At first, the file can only be saved via "save as" and due to Android permissions reasons, the only way to make it appear in the list of recent files is to reopen it.
(2) Due to file permissions, after a "save as", the list of recent files cannot be updated with the new file location.