diff --git a/.gitignore b/.gitignore
index dbe5ef5..1c7a162 100644
--- a/.gitignore
+++ b/.gitignore
@@ -257,3 +257,4 @@ thunderbird-langpacks-3.1.2-20100803.tar.bz2
 /thunderbird-langpacks-78.12.0-20210708.tar.xz
 /thunderbird-78.12.0.source.tar.xz
 /thunderbird-langpacks-78.12.0-20210712.tar.xz
+/thunderbird-78.12.0.processed-source.tar.xz
diff --git a/process-official-tarball b/process-official-tarball
new file mode 100755
index 0000000..f925a84
--- /dev/null
+++ b/process-official-tarball
@@ -0,0 +1,23 @@
+#!/bin/sh
+
+rm -rf ./process-tarball-dir
+mkdir ./process-tarball-dir
+tar -xJf $1 --directory process-tarball-dir
+
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/conformance-checkers/html-rdfa/0030-isvalid.html
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/conformance-checkers/html-rdfa/0008-isvalid.html
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/conformance-checkers/html-rdfa/0030-isvalid.html
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/css/css-ui/support/cursors/woolly-64.svg
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/css/css-ui/support/cursors/woolly.svg
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/conformance-checkers/html-rdfa/0230-novalid.html
+rm -vf ./process-tarball-dir/*/testing/web-platform/tests/conformance-checkers/html-rdfa/0231-isvalid.html
+rm -vf ./process-tarball-dir/*/layout/inspector/tests/chrome/test_fontVariationsAPI.css
+
+processed_tarball=${1/source/processed-source}
+
+cd ./process-tarball-dir
+tar -cf - ./* | xz -9 -T 0 -f > $processed_tarball
+mv $processed_tarball ..
+cd ..
+
+rm -rf ./process-tarball-dir
diff --git a/sources b/sources
index 6da7659..d9c8698 100644
--- a/sources
+++ b/sources
@@ -8,5 +8,5 @@ SHA512 (nspr-4.25.0-1.el8_0.src.rpm) = 7e39e4484b0d504e1b7f1253d7dc1f9f0d45705fb
 SHA512 (cbindgen-vendor-0.14.3.tar.xz) = 33c8d28547674121f690eea0d3ebac33926a39caacac787bf8ed8b346478822e74da5a4a1f57ab4df4105fa8376739a2ece888845a85bc5712aaed20e4a508bc
 SHA512 (nss-3.53.1-3.fc32.src.rpm) = 368849487aa8f9d602c9e5d9d7c88ebd03318aece12470283ff31744ef9eed27ef1e32031378a5a673bb06a9ebbcf5542afa13f3ad465409449c218922189acb
 SHA512 (nodejs-10.21.0-5.fc32.src.rpm) = 4d0c212a2609dc10e242a96f63baa8babb91e8aa6696f66f627c562c1ba30cb3632ed01991c98f48b5942fc7fd89ee34b350f41de901339b49a2c19e979593a7
-SHA512 (thunderbird-78.12.0.source.tar.xz) = 8a9275f6a454b16215e9440d8b68926e56221dbb416f77ea0cd0a42853bdd26f35514e792564879c387271bd43d8ee966577f133f8ae7781f43e8bec9ab78696
 SHA512 (thunderbird-langpacks-78.12.0-20210712.tar.xz) = ea243e0c7dbbd2d81675a106b86d02e55914a67ef56696d43ea5a4f211fdfccbc3e52638c0a8bdb264b7005d4432c475b6b5e7610c614cbf1da3e1e6e1f0d462
+SHA512 (thunderbird-78.12.0.processed-source.tar.xz) = b14ce7b967be0492bb84b707e86c6718c63b8f60a922e942d603677863c98a2c65934f147bc58b545ac59248a9c99cd004303b271e150a58dd53cb8f4b92ad55
diff --git a/thunderbird.spec b/thunderbird.spec
index bcd3d64..eec4b0c 100644
--- a/thunderbird.spec
+++ b/thunderbird.spec
@@ -178,7 +178,7 @@ end}
 Summary:        Mozilla Thunderbird mail/newsgroup client
 Name:           thunderbird
 Version:        78.12.0
-Release:        2%{?dist}
+Release:        3%{?dist}
 URL:            http://www.mozilla.org/projects/thunderbird/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
 Group:          Applications/Internet
@@ -187,14 +187,19 @@ Group:          Applications/Internet
 ExcludeArch:    s390 ppc
 %endif
 
-# From ftp://archive.mozilla.org/pub/thunderbird/releases/%{version}%{?ext_version}/source
-Source0:        https://archive.mozilla.org/pub/thunderbird/releases/%{version}%{?pre_version}/source/thunderbird-%{version}%{?pre_version}.source.tar.xz
+# We can't use the official tarball as it contains some test files that use
+# licenses that are rejected by Red Hat Legal.
+# The official tarball has to be always processed by the process-official-tarball
+# script.
+# Link to official tarball: https://archive.mozilla.org/pub/thunderbird/releases/%%{version}%%{?pre_version}/source/thunderbird-%{version}%{?pre_version}.source.tar.xz
+Source0:        thunderbird-%{version}%{?pre_version}.processed-source.tar.xz
 %if %{build_langpacks}
 Source1:        thunderbird-langpacks-%{version}%{?ext_version}-20210712.tar.xz
 # Locales for lightning
 %endif
 Source2:        cbindgen-vendor-0.14.3.tar.xz
 Source3:        get-calendar-langpacks.sh
+Source4:        process-official-tarball
 
 Source10:       thunderbird-mozconfig
 Source20:       thunderbird.desktop
@@ -1310,6 +1315,9 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #===============================================================================
 
 %changelog
+* Fri Jul 30 2021 Tomas Popela <tpopela@redhat.com> - 78.12.0-3
+- Add script to process the official tarball to comply with PELC review
+
 * Mon Jul 12 2021 Eike Rathke <erack@redhat.com> - 78.12.0-2
 - Update to 78.12.0 build2