behavior has changed based on a non-default value
for that setting.
For example, when `GODEBUG=http2client=0` is set,
`/godebug/non-default-behavior/http2client:events`
counts the number of HTTP transports that the program
has configured without HTTP/2 support.

## Default GODEBUG Values {#default}

When a GODEBUG setting is not listed in the environment variable,
its value is derived from three sources:

pkg math/bits, func Rem64(uint64, uint64, uint64) uint64
pkg mime/multipart, method (*Reader) NextRawPart() (*Part, error)
pkg net/http, method (Header) Values(string) []string
pkg net/http, type Transport struct, DialTLSContext func(context.Context, string, string) (net.Conn, error)
pkg net/http/httptest, type Server struct, EnableHTTP2 bool
pkg net/textproto, method (MIMEHeader) Values(string) []string

pkg net/http, method (*ResponseController) SetWriteDeadline(time.Time) error #54136
pkg net/http, type ResponseController struct #54136
pkg net/http, type Server struct, DisableGeneralOptionsHandler bool #41773
pkg net/http, type Transport struct, OnProxyConnectResponse func(context.Context, *url.URL, *Request, *Response) error #54299
pkg net/netip, func IPv6LinkLocalAllRouters() Addr #51766
pkg net/netip, func IPv6Loopback() Addr #51777

pkg net/http, method (*Transport) CancelRequest(*Request)
pkg net/http, type CloseNotifier interface { CloseNotify }
pkg net/http, type CloseNotifier interface, CloseNotify() <-chan bool
pkg net/http, type Request struct, PostForm url.Values
pkg net/http, type Server struct, TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
pkg net/http, type Transport struct, ResponseHeaderTimeout time.Duration

- api-machinery utility functions `SetTransportDefaults` and `DialerFor` once again respect custom Dial functions set on transports ([#65547](https://github.com/kubernetes/kubernetes/pull/65547), [@liggitt](https://github.com/liggitt))

- Client-go uses the same HTTP client for all the generated groups and versions, allowing to share customized transports for multiple groups versions. ([#105490](https://github.com/kubernetes/kubernetes/pull/105490), [@aojea](https://github.com/aojea))

- Fixed a bug in client-go where new clients with customized `Dial`, `Proxy`, `GetCert` config may get stale HTTP transports. ([#95427](https://github.com/kubernetes/kubernetes/pull/95427), [@roycaihw](https://github.com/roycaihw)) [SIG API Machinery]

- Fixed a bug in client-go where new clients with customized `Dial`, `Proxy`, `GetCert` config may get stale HTTP transports. ([#95427](https://github.com/kubernetes/kubernetes/pull/95427), [@roycaihw](https://github.com/roycaihw)) [SIG API Machinery]

- Fixed a bug in client-go where new clients with customized `Dial`, `Proxy`, `GetCert` config may get stale HTTP transports. ([#95427](https://github.com/kubernetes/kubernetes/pull/95427), [@roycaihw](https://github.com/roycaihw)) [SIG API Machinery]