This website will help you back up your personal data of your Firefox OS device. Technically this means: It will create human readable JSON output out of the binary IndexedDB databases.
In a second step the JSON output can be used to export your data into any other format. The following converters are available out of the box:
While this website's intention is to help Firefox OS users, you can of course use it to export any IndexedDB data.
If you just want to view IndexedDB databases you don't need this website at all: Firefox has an integrated viewer called Storage Inspector already, however you cannot export any data with it.
See the Firefox OS category in my blog for instructions how to use this website.
All data is processed locally on your PC, no data is sent to my server. You may also get the source code from https://github.com/laenion/Firefox-OS-Data-Exporter.