ALT Linux is a family of RPM-based Linux distributions built on the Sisyphus package repository and developed by ALT Linux Ltd together with the international ALT Linux Team community. Past editions cover desktop, server and thin-client use. The default desktop is KDE Plasma (Xfce in the Lite variant), packages are managed with APT-RPM, and several architectures are supported, including AMD64, AArch64 and Elbrus. Sisyphus is the continuously updated development repository, from which more conservative stable branches are cut regularly. Organisations download and install ALT Linux on their own hardware; it is not a hosted service.
ALT Linux is a Russian project and is open source. Because the software runs on your own systems, hosting and data location stay under your control, while the project's package repository, mirrors and wiki are separate infrastructure it operates itself. There is no non-European parent group in the usual sense, but the Russian origin of the developing company and community matters when a European organisation assesses supply-chain trust, update provenance and support arrangements.