diff --git a/internal/ghinstance/host.go b/internal/ghinstance/host.go
index be839d62e..7abfd83ac 100644
--- a/internal/ghinstance/host.go
+++ b/internal/ghinstance/host.go
@@ -26,7 +26,7 @@ func Default() string {
 // reports whether it found the tenant name.
 func TenantName(h string) (string, bool) {
 	normalizedHostName := ghauth.NormalizeHostname(h)
-	return cutSuffix(normalizedHostName, "."+tenancyHost)
+	return strings.CutSuffix(normalizedHostName, "."+tenancyHost)
 }
 
 func isGarage(h string) bool {
@@ -96,11 +96,3 @@ func HostPrefix(hostname string) string {
 	}
 	return fmt.Sprintf("https://%s/", hostname)
 }
-
-// Backport strings.CutSuffix from Go 1.20.
-func cutSuffix(s, suffix string) (string, bool) {
-	if !strings.HasSuffix(s, suffix) {
-		return s, false
-	}
-	return s[:len(s)-len(suffix)], true
-}