Those are the new language tags.
If all went well then you should have a file named: en-GB.plg_content_gnosisplg.ini inside the folder: administrator\language\en-GB
Inside that file are three lines (among many others) that include the weird text that show up in your picture. They are:
PLG_GNOSIS_DEF_TITLE="Definition:"
PLG_GNOSIS_EXA_TITLE="Example:"
PLG_GNOSIS_ETY_TITLE="Etymology:"
I suspect your local installation of Joomla! is using the french language files though. If that is true then we need to COPY the file
en-GB.plg_content_gnosisplg.ini from the
administrator\language\en-GB folder and place it in the
administrator\language\fr_FR folder. Then rename the file
en-GB.plg_content_gnosisplg.ini that is now in your fr-FR folder to
fr-FR.plg_content_gnosisplg.ini
Once you have done, if you want the french translation of the words Definition, Example, and Etymology, then open the
fr-FR.plg_content_gnosisplg.ini file and edit those previously mentioned lines:
PLG_GNOSIS_DEF_TITLE="Definition:"
PLG_GNOSIS_EXA_TITLE="Example:"
PLG_GNOSIS_ETY_TITLE="Etymology:"
to
PLG_GNOSIS_DEF_TITLE="the French word for definition:"
PLG_GNOSIS_EXA_TITLE="the French word for Example::"
PLG_GNOSIS_ETY_TITLE="the French word for Etymology:"
This is really difficult for me to test since I do not have a multilingual installation but theoretically this should translate those strings in your test installation into the french equivalents of Definition, Example, and Etymology. Within a couple days I will have a French/English installation so I can test this for myself.
Let me know if you have any questions about the above.