If you haven't yet heard of Android Silver -- assuming it's real -- that's because it's not been officially announced by Google.

But recent reports from unnamed sources indicate Google is working to replace its Nexus line of pure Android phones with Android Silver devices sometime in 2015.

Nexus has for years been Google's hedge against fragmentation of pure Android by various manufacturers -- including Android bestseller Samsung. These smartphone makers tend to add their own custom apps, interfaces, browsers and services to basic Android.

Nexus smartphones have never been top sellers, but have served as a kind of reference for what pure Android can provide. They tend to be bought by Android enthusiasts and are unlocked from any carrier.

The Information, citing four unnamed sources, this week described Android Silver (subscription required) as taking aim at the high-end iPhone, as well as Samsung and others, by requiring Android Silver phone makers to limit the number of non-Google apps that can be pre-installed, and by giving users the option to uninstall any non-Google apps.

Android Police in early April described Google's Android Silver plan as requiring makers to run the latest version of Android with no, or very limited, customizations. The website relied on slides, allegedly from Google, that it obtained last year.

The Android Silver plan also reportedly calls for Google to pick five Silver phones at one time, and to require carriers to sell them in a special booth within their stores. There could even be a loaner phone for users losing theirs and a Google hangout assistant to provide live video tech support.

All told, Google could be spending up to $1 billion for marketing and support services for Android Silver.

Given the reports already out there about Android Silver, we interviewed several analysts to get their impressions. There are still plenty of unknowns about the concept and those unknowns lead to many questions.

Google isn't commenting on Android Silver.

Here are eight questions raised by the secrecy.

1. Is Android Silver something fundamentally different for Google, or is it more of a rebranding of Nexus?

It's both, if that makes sense, but the rebranding angle holds water, especially if you believe that so much of the success of a new smartphone depends on the marketing and branding behind it.

Jack Narcotta, an analyst at TBRI, weighs in: "Android Silver is more of a revamp of the Nexus program than it is about Google trying to exert more control over the Android ecosystem it's had a large hand in creating. Nexus devices are great and they represent what Android can be when mobile devices aren't saddled with bloatware."

Narcotta noted that Google's use of the name "Nexus" doesn't indicate the device is "Android," which Android Silver could help improve on -- assuming that's the final name. The way products from Nexus are branded is with the name "Google" on the device's startup screen or the name of the manufacturer, such as Asus, in the example of the Nexus 7 tablet.

"Android is too much in the background today and for Google, that's a problem, especially when it's clearly trying to establish Android as its own brand," Narcotta added.

For customers going into a store, a special "Android Silver" booth might be just the branding Google has in mind.

Narcotta expressed some concern about the Android "Silver" moniker instead of another premium name, such as "Platinum" or "Titanium." "The name 'Silver' immediately makes me think Android lost a race and got awarded second place," Narcotta said.

2. Android Silver might indeed be about rebranding Nexus, but isn't it really more than that?

Yes. Several analysts think Google is going to the next level with Android Silver by offering more services to customers than carriers now provide for most Android phones, and even more than what Google provides for Nexus devices.

Google hangouts that offer customer assistance, another possibility, is similar to something Amazon is doing with its new tablets. This customer service idea gets Google out in front of any carrier's customer support.