diff --git a/docs/ALTSVC.md b/docs/ALTSVC.md
new file mode 100644
index 0000000000..bcdf565074
--- /dev/null
+++ b/docs/ALTSVC.md
@@ -0,0 +1,43 @@
+<!--
+Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+
+SPDX-License-Identifier: curl
+-->
+
+# Alt-Svc
+
+curl features support for the Alt-Svc: HTTP header.
+
+## Enable Alt-Svc in build
+
+`./configure --enable-alt-svc`
+
+(enabled by default since 7.73.0)
+
+## Standard
+
+[RFC 7838](https://datatracker.ietf.org/doc/html/rfc7838)
+
+# Alt-Svc cache file format
+
+This is a text based file with one line per entry and each line consists of nine
+space separated fields.
+
+## Example
+
+    h2 quic.tech 8443 h3-22 quic.tech 8443 "20190808 06:18:37" 0 0
+
+## Fields
+
+1. The ALPN id for the source origin
+2. The hostname for the source origin
+3. The port number for the source origin
+4. The ALPN id for the destination host
+5. The hostname for the destination host
+6. The port number for the destination host
+7. The expiration date and time of this entry within double quotes. The date format is "YYYYMMDD HH:MM:SS" and the time zone is GMT.
+8. Boolean (1 or 0) if "persist" was set for this entry
+9. Integer priority value (not currently used)
+
+If the hostname is an IPv6 numerical address, it is stored with brackets such
+as `[::1]`.
diff --git a/docs/HSTS.md b/docs/HSTS.md
new file mode 100644
index 0000000000..85140ab30f
--- /dev/null
+++ b/docs/HSTS.md
@@ -0,0 +1,48 @@
+<!--
+Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+
+SPDX-License-Identifier: curl
+-->
+
+# HSTS support
+
+HTTP Strict-Transport-Security. Added as experimental in curl
+7.74.0. Supported "for real" since 7.77.0.
+
+## Standard
+
+[HTTP Strict Transport Security](https://datatracker.ietf.org/doc/html/rfc6797)
+
+## Behavior
+
+libcurl features an in-memory cache for HSTS hosts, so that subsequent
+HTTP-only requests to a hostname present in the cache gets internally
+"redirected" to the HTTPS version.
+
+## `curl_easy_setopt()` options:
+
+ - `CURLOPT_HSTS_CTRL` - enable HSTS for this easy handle
+ - `CURLOPT_HSTS` - specify filename where to store the HSTS cache on close
+  (and possibly read from at startup)
+
+## curl command line options
+
+ - `--hsts [filename]` - enable HSTS, use the file as HSTS cache. If filename
+   is `""` (no length) then no file is used, only in-memory cache.
+
+## HSTS cache file format
+
+Lines starting with `#` are ignored.
+
+For each hsts entry:
+
+    [host name] "YYYYMMDD HH:MM:SS"
+
+The `[host name]` is dot-prefixed if it includes subdomains.
+
+The time stamp is when the entry expires.
+
+## Possible future additions
+
+ - `CURLOPT_HSTS_PRELOAD` - provide a set of HSTS hostnames to load first
+ - ability to save to something else than a file
diff --git a/docs/Makefile.am b/docs/Makefile.am
index e8f2d55bf3..d944111b1a 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -61,6 +61,7 @@ INTERNALDOCS =                                  \
 EXTRA_DIST =                                    \
  $(CURLPAGES)                                   \
  $(INTERNALDOCS)                                \
+ ALTSVC.md                                      \
  BINDINGS.md                                    \
  BUG-BOUNTY.md                                  \
  BUGS.md                                        \
@@ -82,6 +83,7 @@ EXTRA_DIST =                                    \
  GOVERNANCE.md                                  \
  HELP-US.md                                     \
  HISTORY.md                                     \
+ HSTS.md                                        \
  HTTP-COOKIES.md                                \
  HTTP3.md                                       \
  INSTALL                                        \