Seems it is missing an optional dependency for smartmontools.
Without that you get the following message:
SMART Message: Required tool smartctl not installed. Check --recommends
And for the unsuspecting user, searching for smartctl in pamac you get no results, because that tool is actually provided by the smartmontools package 
PS: When this tool is installed you don’t seem to be needing hddtemp
Did you make a note of it on the project’s page?
No, i would not know where…
Do you mean on the git page GitHub - smxi/inxi: inxi is a full featured CLI system information tool. It is available in most Linux distribution repositories, and does its best to support the BSDs. ?
Or on Projects · Packages / Community / inxi · GitLab ?
The inxi message is clear, check --recommends, which when run will show for missing smartctl the pacman package smartmontools. The --recommends test will show it’s testing for smartctl program, and then at the end, show what package contains that program if it’s an rpm, apt, or pacman based system… In other words, it will show smartctl… missing, then at the end, it will say what package contains that missing program, smartmontools ni this case.
I’ll add it as an optional dependency.
FYI, it looks for the smartctl binary, not the package name.