Lib.rs has previously been editorializing the crates within the search algorithm on their site based on their own personal preference. However, they recently have taken it a step too far in labeling the bitcoin repo as unmaintained despite active development taking place for the past several years. Several others have also taken similar actions.
When I searched “bitcoin”, I found the bitcoin crate, but I had to scroll down a bit.
Oh, you’re right. I see it as the 26th result, down below the “try searching with duckduckgo or on crates.io” notice.