Fred and Preview Compatibility?

I am currently building a site and eyeing to implement Fred for easy maintenance and Preview for a bit of versioning and differentiation between editing and publishing.
I wanted to know if these two Extras even work together before I spend money on Preview.

Preview’s FAQ says:
„… In fact any extras which utalise the core modx_site_content table (i.e. they extend modResource) are compatible with Preview.“

However, I am unable to verify if this is how Fred works.
Can anyone confirm if they work together in theory (if Fred extends modResource)?
Or does someone know how I could check the Fred source code to verify?

Here are the links to both Extras:

Fred does use the modx_site_content table to store the data. (Similar to the way ContentBlocks does.)

But I have never used Preview and can’t tell if these two extra work together.

That sounds great! Thank you for the quick answer.
This is enough of a reason for me to try it.
I will share my experience in this thread once I get around to doing it.