* `h11` - HTTP/1.1 support.
* `certifi` - SSL certificates.
* `chardet` - Fallback auto-detection for response encoding.
+* `hstspreload` - determines whether IDNA-encoded host should be only accessed via HTTPS.
* `idna` - Internationalized domain name support.
* `rfc3986` - URL parsing & normalization.
* `brotlipy` - Decoding for "brotli" compressed responses. *(Optional)*
* `h11` - HTTP/1.1 support.
* `certifi` - SSL certificates.
* `chardet` - Fallback auto-detection for response encoding.
+* `hstspreload` - determines whether IDNA-encoded host should be only accessed via HTTPS.
* `idna` - Internationalized domain name support.
* `rfc3986` - URL parsing & normalization.
* `brotlipy` - Decoding for "brotli" compressed responses. *(Optional)*