there was a source code leak and you can see some examples there which make the president's image more alluring. e.g. if you search for "Putin" they add an invisible "-crab" to your query

that's the most innocent example from the top of my head. There probably are many more serious censorship issues

Yep, plenty, and tbf it's entirely logical. The people working at Yandex do not want find themselves dying of a nerve agent or polonium, which is a real and acute danger for people who displease the ruling regime.

https://hal.science/hal-03217497

https://euvsdisinfo.eu/yandex-from-tech-innovation-to-inform...

https://pmc.ncbi.nlm.nih.gov/articles/PMC10130930/

https://misinforeview.hks.harvard.edu/article/a-story-of-non...