diff --git a/testfiles/api-tag-too-long.luatex.tlg b/testfiles/api-tag-too-long.luatex.tlg
index 0b82e2b..f805f12 100644
--- a/testfiles/api-tag-too-long.luatex.tlg
+++ b/testfiles/api-tag-too-long.luatex.tlg
@@ -1,6 +1,7 @@
 This is a generated file for the l3build validation system.
 Don't change this file in any respect.
-! Package fontspec Error: OpenType tag 'smcpp' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'smcpp' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_feature:nTF {smcpp}
@@ -8,7 +9,8 @@ l. ...\fontspec_if_feature:nTF {smcpp}
 LaTeX does not know anything more about this error, sorry.
 Try typing <return> to proceed.
 If that doesn't work, type X <return> to quit.
-! Package fontspec Error: OpenType tag 'cyrll' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'cyrll' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_script:nTF {cyrll}
@@ -16,7 +18,8 @@ l. ...\fontspec_if_script:nTF {cyrll}
 LaTeX does not know anything more about this error, sorry.
 Try typing <return> to proceed.
 If that doesn't work, type X <return> to quit.
-! Package fontspec Error: OpenType tag 'ROMMM' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'ROMMM' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_language:nnTF {latn}{ROMMM}
diff --git a/testfiles/api-tag-too-long.tlg b/testfiles/api-tag-too-long.tlg
index 0722349..c341894 100644
--- a/testfiles/api-tag-too-long.tlg
+++ b/testfiles/api-tag-too-long.tlg
@@ -1,6 +1,7 @@
 This is a generated file for the l3build validation system.
 Don't change this file in any respect.
-! Package fontspec Error: OpenType tag 'smcpp' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'smcpp' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_feature:nTF {smcpp}
@@ -8,7 +9,8 @@ l. ...\fontspec_if_feature:nTF {smcpp}
 LaTeX does not know anything more about this error, sorry.
 Try typing <return> to proceed.
 If that doesn't work, type X <return> to quit.
-! Package fontspec Error: OpenType tag 'cyrll' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'cyrll' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_script:nTF {cyrll}
@@ -16,7 +18,8 @@ l. ...\fontspec_if_script:nTF {cyrll}
 LaTeX does not know anything more about this error, sorry.
 Try typing <return> to proceed.
 If that doesn't work, type X <return> to quit.
-! Package fontspec Error: OpenType tag 'ROMMM' is too long; script, language, and feature tags must be four characters or fewer.
+! Package fontspec Error: 
+(fontspec)                OpenType tag 'ROMMM' is too long; script, language, and feature tags must be four characters or fewer.
 Type <return> to continue.
  ...                                              
 l. ...\fontspec_if_language:nnTF {latn}{ROMMM}