diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -1255,6 +1255,9 @@
 coreconfigitem('web', 'refreshinterval',
     default=20,
 )
+coreconfigitem('web', 'server-header',
+    default=None,
+)
 coreconfigitem('web', 'staticurl',
     default=None,
 )
diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -2527,6 +2527,9 @@
     Values less than or equal to 0 always refresh.
     (default: 20)
 
+``server-header``
+    Value for HTTP ``Server`` response header.
+
 ``staticurl``
     Base URL to use for static files. If unset, static files (e.g. the
     hgicon.png favicon) will be served by the CGI script itself. Use
diff --git a/mercurial/hgweb/server.py b/mercurial/hgweb/server.py
--- a/mercurial/hgweb/server.py
+++ b/mercurial/hgweb/server.py
@@ -231,6 +231,11 @@
             self.wfile.write('0\r\n\r\n')
             self.wfile.flush()
 
+    def version_string(self):
+        if self.server.serverheader:
+            return self.server.serverheader
+        return httpservermod.basehttprequesthandler.version_string(self)
+
 class _httprequesthandlerssl(_httprequesthandler):
     """HTTPS handler based on Python's ssl module"""
 
@@ -304,6 +309,8 @@
         self.addr, self.port = self.socket.getsockname()[0:2]
         self.fqaddr = socket.getfqdn(addr[0])
 
+        self.serverheader = ui.config('web', 'server-header')
+
 class IPv6HTTPServer(MercurialHTTPServer):
     address_family = getattr(socket, 'AF_INET6', None)
     def __init__(self, *args, **kwargs):
diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -1119,6 +1119,7 @@
             hgrc.write(b'[web]\n')
             hgrc.write(b'address = localhost\n')
             hgrc.write(b'ipv6 = %s\n' % str(self._useipv6).encode('ascii'))
+            hgrc.write(b'server-header = testing stub value\n')
 
             for opt in self._extraconfigopts:
                 section, key = opt.encode('utf-8').split(b'.', 1)
diff --git a/tests/test-archive.t b/tests/test-archive.t
--- a/tests/test-archive.t
+++ b/tests/test-archive.t
@@ -128,7 +128,7 @@
   content-type: application/x-gzip
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=408, sha1=8fa06531bddecc365a9f5edb0f88b65974bfe505
@@ -137,7 +137,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=4c5cf0f574446c44feb7f88f4e0e2a56bd92c352
@@ -145,7 +145,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=cbfa5574b337348bfd0564cc534474d002e7d6c7
@@ -156,7 +156,7 @@
   content-type: application/x-bzip2
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=426, sha1=8d87f5aba6e14f1bfea6c232985982c278b2fb0b
@@ -165,7 +165,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=cbfa5574b337348bfd0564cc534474d002e7d6c7
@@ -173,7 +173,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1450, sha1=71f0b12d59f85fdcfe8ff493e2dc66863f2f7734
@@ -184,7 +184,7 @@
   content-type: application/zip
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1377, sha1=677b14d3d048778d5eb5552c14a67e6192068650
@@ -193,7 +193,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1450, sha1=71f0b12d59f85fdcfe8ff493e2dc66863f2f7734
@@ -201,7 +201,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=4c5cf0f574446c44feb7f88f4e0e2a56bd92c352
@@ -215,7 +215,7 @@
   content-type: application/x-gzip
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=408, sha1=8fa06531bddecc365a9f5edb0f88b65974bfe505
@@ -224,7 +224,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=4c5cf0f574446c44feb7f88f4e0e2a56bd92c352
@@ -232,7 +232,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=cbfa5574b337348bfd0564cc534474d002e7d6c7
@@ -243,7 +243,7 @@
   content-type: application/x-bzip2
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=426, sha1=8d87f5aba6e14f1bfea6c232985982c278b2fb0b
@@ -252,7 +252,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=cbfa5574b337348bfd0564cc534474d002e7d6c7
@@ -260,7 +260,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1450, sha1=71f0b12d59f85fdcfe8ff493e2dc66863f2f7734
@@ -271,7 +271,7 @@
   content-type: application/zip
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1377, sha1=677b14d3d048778d5eb5552c14a67e6192068650
@@ -280,7 +280,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1450, sha1=71f0b12d59f85fdcfe8ff493e2dc66863f2f7734
@@ -288,7 +288,7 @@
   content-type: text/html; charset=ascii
   date: $HTTP_DATE$
   etag: W/"*" (glob)
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
   
   body: size=1451, sha1=4c5cf0f574446c44feb7f88f4e0e2a56bd92c352
diff --git a/tests/test-basic.t b/tests/test-basic.t
--- a/tests/test-basic.t
+++ b/tests/test-basic.t
@@ -12,6 +12,7 @@
   ui.promptecho=True
   web.address=localhost
   web\.ipv6=(?:True|False) (re)
+  web.server-header=testing stub value
   $ hg init t
   $ cd t
 
diff --git a/tests/test-commandserver.t b/tests/test-commandserver.t
--- a/tests/test-commandserver.t
+++ b/tests/test-commandserver.t
@@ -215,6 +215,7 @@
   ui.nontty=true
   web.address=localhost
   web\.ipv6=(?:True|False) (re)
+  web.server-header=testing stub value
   *** runcommand init foo
   *** runcommand -R foo showconfig ui defaults
   ui.slash=True
diff --git a/tests/test-hgweb-commands.t b/tests/test-hgweb-commands.t
--- a/tests/test-hgweb-commands.t
+++ b/tests/test-hgweb-commands.t
@@ -1924,7 +1924,7 @@
   content-length: 12
   content-type: application/mercurial-0.1
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   
   0
   Not Found
diff --git a/tests/test-http-protocol.t b/tests/test-http-protocol.t
--- a/tests/test-http-protocol.t
+++ b/tests/test-http-protocol.t
@@ -50,7 +50,7 @@
   200 Script output follows
   content-type: application/mercurial-0.1
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
 
 Server should send application/mercurial-0.1 when client says it wants it
@@ -59,7 +59,7 @@
   200 Script output follows
   content-type: application/mercurial-0.1
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
 
 Server should send application/mercurial-0.2 when client says it wants it
@@ -68,14 +68,14 @@
   200 Script output follows
   content-type: application/mercurial-0.2
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
 
   $ get-with-headers.py --hgproto '0.1 0.2' --headeronly $LOCALIP:$HGPORT '?cmd=getbundle&heads=e93700bd72895c5addab234c56d4024b487a362f&common=0000000000000000000000000000000000000000' -
   200 Script output follows
   content-type: application/mercurial-0.2
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
 
 Requesting a compression format that server doesn't support results will fall back to 0.1
@@ -84,7 +84,7 @@
   200 Script output follows
   content-type: application/mercurial-0.1
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   transfer-encoding: chunked
 
 #if zstd
@@ -106,7 +106,7 @@
   content-length: 41
   content-type: application/mercurial-0.1
   date: $HTTP_DATE$
-  server: * (glob)
+  server: testing stub value
   
   e93700bd72895c5addab234c56d4024b487a362f