lucy.allakhazam.com field dataFollow

Looking at the spell history for Polychromatic rune:
http://lucy.allakhazam.com/spellhistory.html?id=10674&source=Live

we have:
2006-10-30 20:24 Changed Unknown198 from 1 to 0

On that patch, Polychromatic rune changed from being an "unfocusable" spell to a "focusable" spell.

Ie, before hand, spell casting haste, extension, and other focus effects did not work on Polychromatic rune.

Afterwards, the focus effects worked.

So, I am pretty sure that Unknown198 is the boolean value "Unfocusable".

Hope that helps!