Thank you for your comment and the kind words in it! 
The ASA Stats Mobile was published almost 4 years ago (Play Store and App Store). I don’t have the exact download metrics right now (we can prepare that info for the official proposal); I believe there have been around 1-2K individual users. Our API v1.0 was created solely for the use of the mobile app (the website hadn’t been using any API at that time). Now every part of the ASA Stats uses API v2, the mobile app too.
We just introduced the open source user widgets repository, tho we published the historic data user widget last year as the first/initial widget in the repo. This announcement took place after we developed another user widget - swapping through smart routers. There’s a generic `swapcore` widget, and it is the basis for the currently implemented Folks and Haystack smart routers that derive from it.
Nothing in the official proposal would imply yet-to-be-written code. Here in this thread, we just use some marketing language to explain that the main goal is to have a UI - in the form of a user widget - for all the valid Algorand dApps. 
ASA Stats has been online for 4 years and 9 months. Three times the site was down for about an hour or two, and also we had two major issues with stalled data that lasted for 16 hours (the first one when Algorand Inc. had issues with the Node upgrade and fast catchup wasn’t working) and the second one that lasted for 10 hours (that New Year’s Day when AlgoNode Indexer went down after Orange hit the Mainnet). The proposal is retroactive for the code that has already been published, but the plan is to use the funds to power up another dedicated server that will prevent all the errors besides the Indexer unavailability.
Could you also comment what would be needed in order to open-source also the engine?
I guess the best answer here is to copy/paste a reply to the same question we got on Reddit:
Once the ASA Stats DAO completely takes over the project - currently it only owns the copyright on code - a voting session will be conducted on whether the backend remains closed-source.
Based on the state of the Algorand ecosystem in recent years and the overall interest of the ASA Stats DAO, staying closed-source pretty much ensures continued development of the project, its API, and comprehensive portfolio tracking on Algorand in general.
Last but not least, staying closed-source opens the door to long-term profit and/or an exit for the ASA Stats DAO. For me, as a representative of the ASA Stats Team, the primary and pretty much the only objective is to do everything possible in that regard.