I can't find pale moon 15 on your site, and I am not sure about some strings. So how can I find that version to test?
Pale Moon 15 is in closed beta - the strings are also part of the current beta version that is still being developed, but if you have any questions about the strings, please let me know.
For reference, these strings are present, currently hard-coded in English, in the current release version of Pale Moon, 12.3 R2
The "menu" entries are in the main application menu (they are renames from Firefox's "Add-on Bar" and "Show all bookmarks" respectively)
The "tabs" and "smoothscroll" strings are in the "preferences" window. If you install the language pack for your locale, you can easily see the strings as they will remain in English in the current version.
The "to" string may be unclear, this is used between two durations. "duration: xxx to