FreeMind Reader

Free, no ads. Take your FreeMind mind maps with you! This app displays FreeMind ".mm" files from your file browser, Gmail, Email, Dropbox, Google drive, etc... Long press a node to copy the text and, for nodes that have links, you can copy the link or browse it directly on your device.

Does not include a file browser, so you will need to find the file on your phone or in email first and then click on the file to open the app.