i have done all you said
In my 'Translations/xxx.g.xlf' file :
<?xml version="1.0" encoding="utf-8"?>
<xliff version="1.2" xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="www.w3.org/.../XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
<file datatype="xml" source-language="en-US" target-language="en-US" original="NAViNegoce">
<body>
<group id="body">
<trans-unit id="Report 3761295861 - NamedType 3035507035" size-unit="char" translate="yes" xml:space="preserve">
<source>Dépôt</source>
<note from="Developer" annotates="general" priority="2"></note>
<note from="Xliff Generator" annotates="general" priority="3">Report Packing List - NamedType LocationCaptionLbl</note>
</trans-unit>
</group>
</body>
</file>
</xliff>
in my y 'Translations/xxx.g.en-US' file (or xxx.EN-US, or xxx.fr-FR, or xxx.g.fr-fr, i have tested all) :
<?xml version="1.0" encoding="utf-8"?>
<xliff version="1.2" xmlns="urn:oasis:names:tc:xliff:document:1.2" xmlns:xsi="www.w3.org/.../XMLSchema-instance" xsi:schemaLocation="urn:oasis:names:tc:xliff:document:1.2 xliff-core-1.2-transitional.xsd">
<file datatype="xml" source-language="en-US" target-language="en-US" original="NAViNegoce">
<body>
<group id="body">
<trans-unit id="Report 3761295861 - NamedType 3035507035" size-unit="char" translate="yes" xml:space="preserve">
<source>Dépôt</source>
<target>Location</target>
<note from="Developer" annotates="general" priority="2"></note>
<note from="Xliff Generator" annotates="general" priority="3">Report Packing List - NamedType LocationCaptionLbl</note>
</trans-unit>
</group>
</body>
</file>
</xliff>
I have also test with xxx.fr-FR, (source-language="en-US" target-language="fr-FR"), the file is not used also
the word 'Dépôt' is not translated (but it's ok for all standard fields, like 'Quantity')