Sh Diao reported that CURLOPT_CLOSEPOLICY doesn't work, and indeed, there is

no code present in the library that receives the option. Since it was not
possible to use, we know that no current users exist and thus we simply
removed it from the docs and made the code always use the default path of
the code.

docs/libcurl/curl_easy_setopt.3

@@ -1092,23 +1092,14 @@ value unless you are perfectly aware of how this work and changes libcurl's
 behaviour. This concerns connection using any of the protocols that support
 persistent connections.
 
-When reaching the maximum limit, curl uses the \fICURLOPT_CLOSEPOLICY\fP to
-figure out which of the existing connections to close to prevent the number of
-open connections to increase.
+When reaching the maximum limit, curl closes the oldest one in the cache to
+prevent the number of open connections to increase.
 
 If you already have performed transfers with this curl handle, setting a
 smaller MAXCONNECTS than before may cause open connections to get closed
 unnecessarily.
 .IP CURLOPT_CLOSEPOLICY
-Pass a long. This option sets what policy libcurl should use when the
-connection cache is filled and one of the open connections has to be closed to
-make room for a new connection. This must be one of the CURLCLOSEPOLICY_*
-defines. Use \fICURLCLOSEPOLICY_LEAST_RECENTLY_USED\fP to make libcurl close
-the connection that was least recently used, that connection is also least
-likely to be capable of re-use. Use \fICURLCLOSEPOLICY_OLDEST\fP to make
-libcurl close the oldest connection, the one that was created first among the
-ones in the connection cache. The other close policies are not support
-yet.
+(Obsolete) This option does nothing.
 .IP CURLOPT_FRESH_CONNECT
 Pass a long. Set to non-zero to make the next transfer use a new (fresh)
 connection by force. If the connection cache is full before this connection,