The UI will not stay closed. Part of it has already been opened and rest will follow. And yes, AFAIK you can run Sailfish apps without the closed UI.
Can you run Sailfish apps without the closed UI part?
Yes it does. Google Play, Google Maps, Chrome - all closed source.
Android (AOSP) does not come with any proprietary Google applications
But then you don't get to call it "Android", and you don't get Google Play, Maps, etc.
You can download the complete source for AOSP, compile it, put it on your phone, and run only open source applications
Google Play is the official package manager for Android. It's not a very open system where the package manager is proprietary and implements DRM.
Again... the UI will be open sourced. Continuing to ignore this fact will only make you look stupid. The entire rest of Sailfish is open source (various licenses), only part of the UI is closed (for now), and it will be allowed to redistribute, fork, modify etc. Sailfish, just like any open source software.
A closed source UI on top of an open source kernel+libraries is not "more open" than an open source UI on top of an open source kernel+libraries.
Is it allowed to redistribute modified versions of Sailfish? Is the license GPL compatible? Can you distribute Sailfish and bundled GPL apps? You won't be able to if Sailfish apps link to a proprietary UI library. It's not free.
I don't think you understand. From Wikipedia:
Clearly false. About 15% of commits to the base Android project alone come from non-Google employees. And if you consider the commits to projects that Android relies on (Webkit, Linux kernel etc.) then contributors are coming from coders everywhere.
"The Open Handset Alliance develops the changes to the Linux kernel, in public, with source code publicly available at all times. The rest of Android is developed in private by Google, with source code released publicly when a new version is released."
Android is developed in secret, by Google, and source code only released with releases of the OS. It doesn't use any of the usual Linux software stack, such as glibc, GNU userland tools, even the shell is from NetBSD. It's entirely non-standard.
By contrast, both Tizen and Sailfish are glibc-based, use systemd, standard userland tools, and Wayland. Sailfish has an open development model, where core parts of the OS are developed in a meritocracy, by community, anyone can join in the development. It's all done in the open. Only the UI (which is roughly equivalent to a Desktop Environment) is being developed in secret by Jolla for now, which is understandable because they haven't released their first phone yet - they probably just want to prevent a competitor plagiarizing them and undercutting their efforts. Which is an understandable concern for a small startup with limited legal resources. The UI will be opened fully though.
Which is why I specified "to an extent". Which is true, as parts of Ubuntu are developed in secret, under a closed development model. For example, look at what they did with Mir, developed in secret for six months. And they do have other skunkworks projects as well.
And to claim that Ubuntu has a closed development model is just insane.
Now you're just being silly. You're using circular logic. If you define "Sailfish" as "only the parts that are not from other contributors" then of course there are no other contributors! You can't frame the argument in that way, because it would be pointless.
And most of Ubuntu is from Debian, which includes a lot of other contributors. But that is not what I asked - I asked how many commits to the actual Sailfish project come from outside contributors? Not other projects that Sailfish incorporates, but the actual Sailfish project. Saying that Sailfish has many external contributors because it incorporates other open source projects is like saying that OS X has many external contributors because it does the same.
Mer is the core system of Sailfish. It's maintained in large part by Jolla, but there are many other contributors. Sailfish also depends on other technologies: Qt, Wayland, libhybris, systemd. There are no hard limits of what is "actual Sailfish" because that's how open source works, projects overlap and reuse the same code - that's one of the benefits of open source.
How many non-Google people contribute on Surfaceflinger? How many non-Android systems use Bionic? How many non-Ubuntu systems use Mir? Sailfish uses technologies that are being developed by the community, for the community, and contributes in upstream development, instead of NIH'ing every step of the way.