Yes, it's another port of the Solarized theme.
What's different in this one? Nothing, I think. It's just the Solarized theme forked from its original source (from Ethan's repo) with some customizations to make it more comfortable to me.
Through lazy:
{
"gustavofsantos/solarized.nvim",
priority = 1000,
opts = {},
config = function()
vim.cmd([[colorscheme solarized]])
end,
}Checkout the wiki page