There are sans serif fonts where serifs are used sporadically:
My questions are:
Do these parts are real serifs, i.e. will typeface designers call them serifs or by any other names?
Is there a name for the phenomenon? (using "serifs" in sans-serifs") helping to find all the "mix" fonts by some keyword etc?
I found letters I-T-S-Y-C with such "serifs", are there other "serifs-in-sans" letters?