System collation and system timezone data

(Maybe this is two separate issues?)

It's common for runtimes (or apps) to have to bundle entire copies of collation tables, timezone data, etc with every app distributed. It adds a considerable amount of weight and for web deployment situations it could make things a lot worse - i.e. do we really want people to have to drag along 2-5mb worth of data with every little worker they want to run on edge nodes just because they need to sort strings?

It would make sense for host environments to be able to expose collation, timezone, etc data they have available to the application. Most environments that can host a wasm app have this data already - every browser has to ship ICU, etc.

AFAIK Mono currently ships its own timezone database on some platforms for this reason, and I see people ship ICU everywhere in all sorts of scenarios. It'd be cool if WASI could at least optionally eliminate the need to ship your own copies of ICU and tzdb.

Start by separating the collation and timezone proposals, then review the stated WASI goal of letting host environments expose data already available to applications. Compare the stated concerns about ICU and tzdb, and consider the work complete only when the scope and optional interface requirements are clearly decided.