Change Thunderbird background color

To change the background color for Thunderbird message pane, which seems
not to be possible via the UI, do the following:
* Access the configuration editor via Preferences > Config Editor
* Change the value of the setting "browser.display.background_color"

Enable encrypted formatting in Disk Utility in macOS

If the option to select the encrypted format type doesn't appear when using Disk Utility in macOS, you may need to change the partition scheme, e.g., change to GUID Partition Table:

1. Disk Utility > View > Show All Devices
2. Go to root of the target drive then select "Erase"
• Format: APFS (Encrypted)
• Scheme: GUID Partition Map
  

Note: Mac OS Extended (HFS+) is the previous file system from Apple, but APFS is currently recommended, unless there are compatibility issues with systems before macOS High Sierra, or if you want to use the drive with Time Machine on macOS Catalina or older.

References
Disk management command line: https://www.theinstructional.com/guides/disk-management-from-the-command-line-part-2
No partition scheme option: https://apple.stackexchange.com/questions/304131/no-partition-scheme-option-when-erasing-a-usb-disk-in-macos-high-sierra
Comparison of macOS file systems: https://www.techrepublic.com/article/apfs-vs-hfs-which-apple-filesystem-is-better/

Adding custom sound effects to macOS

In order to add custom sound effects to macOS, you need to copy the new sound files into the directory "~/Library/Sounds/" located in your home directory. The file name will be used to designate the new sound effect in the Sound panel of the System Preferences dialog. You can then select this new sound effect as the default alert sound.

Note that sound effect files need to be in the AIFF format; files in this format can be created via the iTunes application. Moreover, sample AIFF files can be found in the "/System/Library/Sounds/" which contains the built-in macOS sound effects.

File userChrome.css not working for Thunderbird/Firefox

Newer versions of Thunderbird and Firefox (starting around 2019) disable by default the loading of the 'userChrome.css' file used to configure display preferences. To enable it, you must enable via the Config Editor the setting called toolkit.legacyUserProfileCustomizations.stylesheets.

Reference: https://www.userchrome.org/how-create-userchrome-css.html

Display unified CJK characters in macOS terminal as Japanese characters

Without some specific language information (such as the "lang" attribute in HTML), unified CJK Unicode characters are displayed by default in a generic manner. However, users of a certain language would prefer to see the particular character version for that language even in the terminal.

This is possible in macOS by adding that language as a preferred one. For example, in order to display unified CJK characters in a macOS terminal as Japanese characters, you have to:

• Go to System Preferences > Language & Region
• Add the Japanese language to the "Preferred languages" panel

Note that you will need to restart the Terminal app before changes take effect.