fixup! Base Browser strings

TB 43624: Tweak the string letterboxing-size-status.

NOTE: The string has not yet reached translators, so we do not need to
change the ID.

toolkit/locales/en-US/toolkit/global/base-browser.ftl

@@ -17,14 +17,15 @@ basebrowser-rfp-maximize-warning-message = Maximizing the browser window can all
 basebrowser-rfp-restore-window-size-button-label = Restore
 basebrowser-rfp-restore-window-size-button-ak = R
 
-## Letterbox size indicator (appearing on the bottom of the viewport)
+## Letterboxing size indicator.
 
-# Shows the current tab's letterboxed vieport size when resizing.
-# "Letterbox(ing)" should be treated as a feature/product name, and likely not changed in other languages.
+# Shows the current tab's Letterboxing dimensions in the bottom corner when resizing the window.
+# The word "Letterboxing" is the proper noun for the Tor Browser feature, and is therefore capitalised.
+# "Letterboxing" should be treated as a feature/product name, and likely not changed in other languages.
 # The "×" symbol is a unicode (U+00D7) symbol for multiply.
 # $width (Number) - The window width. The "NUMBER" function will format this number to the same locale, and the "useGrouping" option will remove grouping symbols, like thousand separators.
 # $height (Number) - The window height.
-letterboxing-size-status = Letterbox size: { NUMBER($width, useGrouping: "false") } × { NUMBER($height, useGrouping: "false") }
+letterboxing-size-status = Letterboxing size: { NUMBER($width, useGrouping: "false") } × { NUMBER($height, useGrouping: "false") }
 
 ## Tooltip for the about:addons recommended badge