Manual:$wgHTTPMaxConnectTimeout

HTTP client: $wgHTTPMaxConnectTimeout
The maximum HTTP connect timeout in seconds.
Introduced in version:1.35.0 (Gerrit change 596539; git #504fe2af)
Removed in version:still in use
Allowed values:(float or integer)
Default value:0 (1.38+)
INF (1.35-1.37)

Details edit

The maximum HTTP connect timeout in seconds. If any specified or configured connect timeout is larger than this, then this value will be used instead.

Zero is interpreted as "no limit".