I think this is the definition of the citecounter option on the biblatex package:
\DeclareBibliographyOption[boolean]{citecounter}[true]{%
\ifcsdef{blx@opt@citecounter@#1}
{\csuse{blx@opt@citecounter@#1}}
{\blx@err@invopt{citecounter=#1}{}}}
\def\blx@opt@citecounter@true{%
\let\blx@setcitecounter\blx@setcitecounter@global
\let\blx@citecounter\blx@citecounter@global
\let\abx@aux@count\blx@aux@count
\let\abx@aux@fncount\blx@aux@fncount
\booltrue{citetracker}}
\def\blx@opt@citecounter@context{%
\let\blx@setcitecounter\blx@setcitecounter@context
\let\blx@citecounter\blx@citecounter@context
\let\abx@aux@count\blx@aux@count
\let\abx@aux@fncount\blx@aux@fncount
\booltrue{citetracker}}
\def\blx@opt@citecounter@false{%
\let\blx@setcitecounter\relax
\let\blx@citecounter\relax
\let\abx@aux@count\@gobbletwo
\let\abx@aux@fncount\@gobbletwo}
Then, what can I use to know whether the option was enabled?
For example:
\usepackage[style=abnt,language=english,citecounter=false]{biblatex}
\if citecounter=false
\message{Citecounter is false^^J}
\else
\message{Citecounter is enabled^^J}
\fi
Related:
citetrackerbool as tested with\ifcitetrackeris activated by several options (citecounterbeing one of them) and need not mean that the tracking optioncitetrackerhas been enabled. – moewe Apr 08 '19 at 07:05