Rybar? Rybar (of Telegram channel) is confirmed to be Mikhail Zvinchuk, "a career officer in the [Russian] armed forces."
https://novayagazeta.eu/articles/2022/11/25/byvshii-sotrudnik-press-sluzhby-minoborony-mikhail-zvinchuk-podtverdil-chto-iavliaetsia-avtorom-telegram-kanala-rybar-news
A 31-year-old former employee of the press service of the Ministry of Defense confirmed that he is the creator and administrator of the telegram channel Rybar. He acknowledged the authorship in an interview with RTVI.
“I am indeed the founder, as I call it, of the project “Rybar” <...> Indeed, I am a former employee of the press service of the Ministry of Defense, the Department of Information and Mass Communications. The experience I gained from working in the armed forces, I capitalized in order to engage in my own information activities,” he said.
Zvinchuk said that he is a career military officer. He also confirmed the previously published information that he studied at the Military University under the Ministry of Defense as an Arabic language interpreter. According to Zvinchuk, he served in Special Forces, worked as an interpreter for one year in Syria and six months in Iraq.
Earlier, The Bell published an investigation, which revealed the identity of the creator and the chief administrator of the anonymous pro-government telegram channel “Rybar” with an audience of millions. The publication claimed that it was run by a former employee of the press service of the Russian Defense Ministry, 31-year-old Mikhail Zvinchuk.
The publication said that journalists were contacted by one of the readers, who claimed to know the creator of “Rybar”. He shared the phone number of the author of the telegram channel, and the journalists were able to identify him.