brandShorterName is missing from brand.properties
When I open about:preferences in Tor Browser 5.0 (and probably also in 5.5a1), I see this message:
*** Failed to get string brandShorterName in bundle: chrome://branding/locale/brand.properties
This is because we only added brandShorterName to the brand.dtd file in Torbutton; we also need to add it to brand.properties.
One user visible problem that results is that "Tor Browser" is not disabled to the left of the URL for chrome URLs such as about:config.