A series of articles by Bart Hendricks on the probable cooperation of private Russian space companies with their Chinese counterparts: Stilsat-1: Russian-owned, Chinese-built satellite watching Ukraine (Part 1) (11/03/2025).
Stilsat-1: Russian-Owned, Chinese-Built Satellite Watching Ukraine (Part 2) (11/10/2025).
Flying Under the Radar: Russia's Tacit Reliance on Chinese SAR Satellites (Part 1) (10/12/2026).
Flying Under the Radar: Russia's Tacit Reliance on Chinese SAR Satellites (Part 2) (10/19/2026) Hendricks posts copies of his papers on the NSF forum, Soyuz, Progress, and Unmanned. There you can find the attachments of the documents it refers to.