Thanks to  Simone Mannini IW5EDI -May 28, 20202039 – DX Zone

With the new WSJT-X version 2.2.0-rc2, now available for downloading from the WSJT-X website the WSJT-X development team has also published additional FT8 “overflow” frequencies:

Increasing FT8 usage on the popular bands 40, 30, and 20m means that
the default 3 kHz sub-bands are often wall-to-wall with signals.
Overcrowding encourages some to turn on their amplifiers, which only
makes things worse.  We are trying to coordinate the suggested
frequencies in WSJT-X with updated band plans being considered by
IARU, ARRL, and other amateur radio societies.

On a trial basis, and in response to numerous suggestions from around
the world, we have added a second set of suggested dial frequencies
for FT8 on three HF bands and also on 6 meters. The new suggested dial
frequencies are 7.071, 10.133, 14.071, and 50.310 MHz.  These
frequencies will appear in your drop-down band-selector list after you
go to the "Settings | Frequencies" tab, right-click on the frequency
table, and select "Reset".  Alternatively, you can add the new FT8
frequencies manually.

When the conventional FT8 sub-band on 6, 20, 30, or 40 m seems too
full, please try moving your dial frequency down 3 kHz!  Be aware that
as currently implemented, WSJT-X will set your dial to the lowest
frequency for the selected mode and band, when you switch bands.

We’ve updated our list of FT8 Frequencies page accordingly.