Have the highlighting groups been renamed?

[hesxenon]

I was trying to get colored indent guides and was met with an error that RainbowRed wasn't defined. Looking through the highlight groups I noticed that there is RainbowDelimiterRed and such... maybe lazy vim installed rainbow-delimiteris.nvim without directly showing it, or were the highlight groups renamed?

[lukas-reineke]

Neither RainbowRed nor RainbowDelimiterRed are, or were ever, part of indent-blankline.

RainbowDelimiterRed is from rainbow-delimiteris.nvim
and RainbowRed is just an example in the readme of how you can define your own highlight groups.