The Bug:

Any labels used for the Quick Play feature (such as "custom", "singleplayer", "multiplayer", "creative", or "survival") are untranslatable.

Steps to Reproduce:

• Open the Launcher in the version stated.
• Set the language to something that is not English (Settings) and enable experimental features.
• Click on the Minecraft: Java Edition tab.
• Go to Quick Play look for the strings "custom", "singleplayer", "multiplayer", "creative" or "survival".

→  Regardless of the language selected, every label remains in English.

Observed Behavior:

All labels are untranslatable.

Expected Behavior:

All labels would be translatable.

Notes:

• Attempt to search for the existence of these strings by using this search filter on the official Minecraft Launcher project on Crowdin.
• Take note as to whether or not these strings are untranslatable.