Extension Settings "Something's gone wrong", fresh Ubuntu 19.10 install

[brewmanz]

Completely fresh, first time ever, empty drive, 'Ubuntu 19.10 amd64' install
..
Processor: Instel Core i5-4310M CPU @ 2.70 x 4
Graphics: Quadro K2100M/PCIe/SSE2
GNOME: 3.34.2
OS type: 64-bit
Disk: 160.0GB
..
All updates then applied.
..
Then I wanted to change date & time format,
Follow suggestions to install this extension,
press 'Extension Settings' and get
"Something's gone wrong"
"We're very sorry .... [etc]"
Technical Details:
The settings of extension [email protected] had an error:

TypeError: extension.metadata.formatTargets is undefined

Stack trace:

buildPrefsWidget@/home/bryan/.local/share/gnome-shell/extensions/[email protected]/prefs.js:136:2
_showPrefs@resource:///org/gnome/shell/extensionPrefs/main.js:57:22
vfunc_command_line@resource:///org/gnome/shell/extensionPrefs/main.js:351:23
main@resource:///org/gnome/shell/extensionPrefs/main.js:707:5
@<main>:1:43

====
Different stack trace to #16
Different stack trace to #12

[brenfwd]

See #16 (comment) for a workaround