Expanded Psionics Handbook introduced a new use of the Concentration skill to gain psionic focus, which can then be expended in order to “take 15” on a future Concentration check. Various psionic feats and class features function only while focused, or require you expend that focus in order to activate some effect.
Importantly, only characters who have at least 1 power point available can gain psionic focus.
Is psionic focus—either gaining it, maintaining it, or expending it—inherently “psionic,” that is, suppressed by null psionics field?
The descriptions in Expanded Psionics Handbook for neither gaining psionic focus nor null psionics field, but Complete Psionic included a lot of really dumb stealth changes to psionics, so it’s difficult for me to rule out anything being found there. Psionic feats, which are some of the most significant sources of things powered by psionic focus, are explicitly supernatural, for example, but for the purposes of this question I am curious about other things that aren’t so explicit, such as basic the “expend focus to take 15” effect.