diff --git a/800.renames-and-merges/firefox.yaml b/800.renames-and-merges/firefox.yaml
index 71ff0dd9a..f33b88201 100644
--- a/800.renames-and-merges/firefox.yaml
+++ b/800.renames-and-merges/firefox.yaml
@@ -4,7 +4,7 @@
 - { setname: firefox,                  namepat: "firefox-esr[0-9.-]*(-l10n|-i18n|-gtk2|-privacy)*", addflavor: $1 }
 - { setname: firefox,                  namepat: "firefox[0-9.-]*esr" }
 - { setname: firefox,                  namepat: "firefox-esr-(i18n-.*)", addflavor: $1 }
-- { setname: firefox,                  namepat: "firefox\\.esr\\.([a-z]{2,3}(?:-[a-z]+))", addflavor: $1 }
+- { setname: firefox,                  namepat: "firefox\\.esr\\.([a-z]{2,3}(?:-[a-z]+)?)", addflavor: $1 }
 - { setname: firefox,                  name: firefox-legacy }
 
 - setname: firefox
diff --git a/800.renames-and-merges/t.yaml b/800.renames-and-merges/t.yaml
index 80aabcdcf..d0398ab10 100644
--- a/800.renames-and-merges/t.yaml
+++ b/800.renames-and-merges/t.yaml
@@ -122,7 +122,7 @@
 - { setname: thunarx-python,           name: thunarx-python-0.3 }
 - { setname: thunder-and-lightning,    name: "thunder&lightning" }
 - { setname: thunderbird,              name: [mozilla-thunderbird,mozillathunderbird,thunderbird-esr] }
-- { setname: thunderbird,              namepat: "thunderbird\\.([a-z]{2,3}(?:-[a-z]+))", addflavor: $1 }
+- { setname: thunderbird,              namepat: "thunderbird\\.([a-z]{2,3}(?:-[a-z]+)?)", addflavor: $1 }
 - { setname: thunderbird,              name: [thunderbird-45-gtk2,thunderbird-gtk2], addflavor: gtk2 }
 - { setname: thunderbird,              name: mozilla-thunderbird-l10n, addflavor: l10n }
 - { setname: thunderbird,              name: [thunderbird-bin,thunderbird-i18n,thunderbird-l10n-xpi,thunderbird-ru,thunderbird-kde,thunderbird-it,thunderbird-en-us,mozilla-thunderbird-bin,thunderbird-globalmenu,thunderbird-it-bin-wayland,thunderbird-bin-fr,thunderbird-en-us-bin-wayland], addflavor: true }