1Exuberant ctags generates following tags file
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3	$ ctags -o - --C-kinds='x'  input.h
4	C	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^class C;$/;"	x
5	S	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^struct S;$/;"	x
6	a	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^extern int a;$/;"	x
7	b	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^extern struct B b;$/;"	x
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9Universal ctags generates following tags file
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11	$ ./ctags -o - --kinds-C='x'  input.h
12	a	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^extern int a;$/;"	x	typeref:typename:int
13	b	/home/jet/var/ctags/Units/review-needed.r/extern_variable.h.t/input.h	/^extern struct B b;$/;"	x	typeref:struct:B
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15I marked this .b. We have to consider which behavior is better.
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