client or server to have an empty Content-Length header.
This behavior is controlled by the `httplaxcontentlength` setting.
+Go 1.22 changed the behavior of ServeMux to accept extended
+patterns and unescape both patterns and request paths by segment.
+This behavior can be controlled by the
+[`httpmuxgo121` setting](/pkg/net/http/#ServeMux).
+
+
### Go 1.21
Go 1.21 made it a run-time error to call `panic` with a nil interface value,