docs.rs: building fewer targets by default

Building fewer targets by default On 2026-05-01 , docs.rs will make a breaking change to its build behavior. Today, if a crate does not define a targets list in its docs.rs metadata , docs.rs builds documentation for a default list of five targets. Starting on 2026-05-01 , docs.rs will instead build documentation for only the default target unless additional targets are requested explicitly. This is the next step in a change we first introduced in 2020, when docs.rs added support for opting into fewer build