Architecture specific change in rpms/firefox.git

The package rpms/firefox.git has added or updated architecture specific content in its
spec file (ExclusiveArch/ExcludeArch or %ifarch/%ifnarch) in commit(s):
https://src.fedoraproject.org/cgit/rpms/firefox.git/commit/?id=144b07dd715e4....

Change:
+ExclusiveArch: %{ix86} x86_64

Thanks.

Full change:
============

commit 496ab707ce0bab0e8f49ef67a24534cf51499530
Merge: 936095b 144b07d
Author: Martin Stransky 
Date:   Fri Sep 29 11:54:46 2017 +0200

Merge branch 'master' into f26

commit 144b07dd715e45a4480c5ebd210841bb8cf6c04b
Author: Martin Stransky 
Date:   Fri Sep 29 11:54:28 2017 +0200

Let's build *something* at least

diff --git a/firefox.spec b/firefox.spec
index 27531ab..5b582ab 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -1,3 +1,5 @@
+ExclusiveArch: %{ix86} x86_64
+
 # Use ALSA backend?
 %define alsa_backend      0