Astra Linux

Astra Linux is a Russian Linux-based computer operating system (OS) developed to meet the needs of the Russian army, other armed forces and intelligence agencies. It provides data protection up to the level of "top secret" in Russian classified information grade. It has been officially certified by Russian Defense Ministry, Federal Service for Technical and Export Control and Federal Security Service.
Specifications.
The creator of the OS is the Scientific/Manufacturing Enterprise Rusbitech which is applying solutions according to Russian Government decree №2299-р of 17/10/2010 that orders federal authorities and budget institutions to implement Free Software use. 
The OS releases are named after Hero Cities in Russia and Commonwealth of Independent States (CIS). There is one release for "general purpose" code named "Oryol" aimed at "achieving small and mid-business goals". Other releases are marked "special purpose" – the "Smolensk" for x86-64 PCs, "Tula" for networking hardware, "Novorossiysk" for ARM mobile devices and "Murmansk" for IBM System Z mainframe computers.
Rusbitech also manufactures a "soft/hardware trusted boot control module" MAKSIM-M1 ("М643М1") with PCI bus. It prevents unauthorized access and offers some other raised digital security features. The module, besides Astra Linux, also supports OSes with Linux kernel 2.6.x up to 5.x.x, as well as several Microsoft Windows OSes.
It is declared the Astra Linux licenses correspond with Russian and international laws and "don't contradict with the spirit and demands of GPL license". The system uses .deb packages.
Astra Linux is considered a recognized Debian derivative, Rusbitech has partnership relations with The Linux Foundation and The Document Foundation.
Use.
The Special Edition version (paid) is used in many Russian state-related organizations. Particularly, it is used in the Russian National Center for Defence Control.
There are talks to deploy mass use of Astra Linux in many state institutions of the Republic of Crimea – legitimate use of other popular OSes is questionable because of international sanctions during the Ukrainian crisis.
Also there are plans on cooperation of Rusbitech and Huawei.
In January 2018, it was announced that Astra Linux was going to be deployed to all Russian Army computers, and Microsoft Windows will be dropped.
In February 2018, Rusbitech announced it has ported Astra Linux to Russian-made Elbrus microprocessors.
In February 2019, Astra Linux was announced to be implemented at Tianwan Nuclear Power Plant in China.
Since 2019 "super-protected" tablet computers branded "MIG" are available with Astra Linux, smartphones are expected.
In 2019 Gazprom national gas/oil holding announced Astra Linux implementation, in 2020 nuclear corporation Rosatom, in early 2021 Russian Railways was reported to do so.
In 2020, Astra Linux sold more than a million copies in licenses and generated 2 billion rubles in sales.