I'd like to make it go away, but as a simple k-> v store it's decent enough. Web SQL provided relational data and aggregation, something that's sorely lacking from IndexedDB (and the libraries that build on top of it, poorly replicating SQL in the browser).

The amount of client side code one has to write to replicate simple SQL group by/sum operations is mind numbingly bad -- not to mention performance hit vs. SQLite's blazing native C performance (and it shipped with the browser to boot, no separate download of some lousy bloated 3rd party JS library).