6.3.3 rainbow does not work from cron and shell

Software [CZ] SW chyby-diskuze [CZ]
#1

root@turris:~# cat /etc/cron.d/rainbow
MAILTO=""
0 18 * * * root /usr/bin/rainbow intensity 5
0 8 * * * root /usr/bin/rainbow intensity 100
root@turris:~# /usr/bin/rainbow intensity 5
Command failed: Not found
Command failed: Not found

#2

Today was released new version TurrisOS (6.4.0) with new version of rainbow package.
Maybe it helps you …
https://forum.turris.cz/t/turris-os-6-4-0-is-released-now/19169