Pre-release documentation for Calls says:
Calls can be used in filters. The text is not wikified which again means that the parameters will be ignored.
Testing using <<now>> macro with : vs = param handling:
<$let fmt="YYYY0MM0DD0hh0mm0ss0XXX">
#literal unnamed param<br><<now YYYY0MM0DD0hh0mm0ss0XXX>>
#literal named param using `:`<br><<now format:'YYYY0MM0DD0hh0mm0ss0XXX'>>
#variable named param using `=`<br><<now format=<<fmt>>>>
#filter with unnamed param<br><$list filter="[<now YYYY0MM0DD0hh0mm0ss0XXX>]"><<currentTiddler>></$list>
#filter with literal named param using `:`<br><$list filter="[<now format:'YYYY0MM0DD0hh0mm0ss0XXX'>]"><<currentTiddler>></$list>
#filter with variable named param using `=`<br><$list filter="[<now format=<<fmt>>>]"><<currentTiddler>></$list>
produces this output:
literal unnamed param
20260224084305886
literal named param using :
20260224084305886
variable named param using =
20260224084305886
filter with unnamed param
20260224084305886
filter with literal named param using :
20260224084305886
filter with variable named param using =
Filter error: Missing [ in filter expression
Thus, calls in filters using the unnamed param or : literal named param syntax still work, even though Calls seems to say otherwise.