Content of indexedDB in human readable format


I have to retrieve and process data from the indexedDB of a running app on an Android device
I managed to extract it via adb :
adb exec-out run-as io.ionic.starter tar c app_webview/Default/IndexedDB/file__0.indexeddb.leveldb/ > extracted.tar

I got a bunch of .ldb files which seem to contain what I need, but they are compressed in an unknown format
How can I read those file ?

thanks !