Waterfox: shared object "libicui18n.so.62" not found, required by "libxul.so"

[Graham Perrin]

$ waterfox
XPCOMGlueLoad error for file /usr/local/lib/waterfox/libxul.so:
Shared object "libicui18n.so.62" not found, required by "libxul.so"
Couldn't load XPCOM.
$ date ; uname -v
Sun 28 Oct 2018 22:31:00 GMT
FreeBSD 13.0-CURRENT r339737 GENERIC-NODEBUG
$

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Is there any easy-ish way to work around this?

A downgrade to 12.0-BETA2, maybe?

(I know, the www/waterfox was deleted but I'd like to continue using it for as long as possible.)

TIA