a question about $(call function

[ali hagigat]

8.6 The call Function
If variable is the name of a builtin function, the builtin function is
always invoked (even
if a make variable by that name also exists).
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In the following example with make, 3.81 why var2 is aba?

kk=$(1)00
aba=$(1)11
var1=kk
$(call var1)=aba
var2=$(call $(call var1),pp)
all: ;
$(warning var2=$(var2))


makefile27:7: var2=aba