Flmngr shows only images in the files list
Check context
Flmngr file manager is capable of working with various file types. However, when acting as a CKEditor or TInyMCE plugin, it might only show images because it opens in the image selection context. When you insert a new image widget or attempt to change an existing image, Flmngr switches to the image selection mode and conceals other file types.
To see all files, please use the "Browse" button without a selection inside the editor. Also when you select a Link/Button widget, the file manager will not filter files by extensions (but it will if you selected Image, Gallery, or another similar widget).
Check accepted extensions
When calling Flmngr programmatically via API, check if there is an acceptExtensions parameter in your Flmngr configuration. By default, this parameter is null, meaning that any file extension is accepted. If you have limited the extensions by using this parameter, but wish to see some other types of files, please add the desired extensions to the acceptExtensions parameter.