It's possible that the .io cctld is going to go away [0]. Does crates.io have a backup plan at all? Does anyone know what problems it would end up causing?
I imagine the package registry having to move domains is going to cause a ton of problems.
Frankly, it's concerning to me that so much of the Rust ecosystem has chosen to standardize on shaky ccTLDs. The Indian Ocean Territory (.io) is a small island territory whose only inhabitants are a single military base, it is crazy to use that domain for something important. Serbia (.rs) is more stable, but they could still cut off access for non-Serbians if they wanted to.
[0] - https://en.wikipedia.org/wiki/.io#Phasing_Out
Obviously this isn't specific to Rust, but frankly it's bizarre to me that ICANN chose to tie top-level domains to country codes in the first place. Languages might have made sense, but a major feature of the internet is that it's less beholden to political boundaries than most of the physical world is.
It makes a lot of sense for businesses, especially where different countries might have different regulations. E.g., amazon.ca and amazon.in. Both sites are in English but it makes way more sense to split them up by country.
Why top-level, though? Why not amazon.in.com?
Interestingly enough, you also have amazon.co.uk, which combines the nature (commercial) and location served (UK), but in the opposite order.