/usr/include/thunderbird/gmock/ is in thunderbird-dev 1:38.6.0+build1-0ubuntu1.
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/usr/include/thunderbird/gmock/gmock-actions.h
/usr/include/thunderbird/gmock/gmock-cardinalities.h
/usr/include/thunderbird/gmock/gmock-generated-actions.h
/usr/include/thunderbird/gmock/gmock-generated-function-mockers.h
/usr/include/thunderbird/gmock/gmock-generated-matchers.h
/usr/include/thunderbird/gmock/gmock-generated-nice-strict.h
/usr/include/thunderbird/gmock/gmock-matchers.h
/usr/include/thunderbird/gmock/gmock-more-actions.h
/usr/include/thunderbird/gmock/gmock-spec-builders.h
/usr/include/thunderbird/gmock/gmock.h
/usr/include/thunderbird/gmock/internal/
/usr/include/thunderbird/gmock/internal/gmock-generated-internal-utils.h
/usr/include/thunderbird/gmock/internal/gmock-internal-utils.h
/usr/include/thunderbird/gmock/internal/gmock-port.h