porting from ANTLR2 to ANTLR4

[gurucubano]

With the help of GitHub Copilot I ported the grammar file InfoGuideQuery.g to InfoGuideQuery.g4. Also the Java code is changed accorgingly, compiles and runs with ANTLR4. I'm attaching the InfoGuideQuery.g4 here. What I do not understand is this detail:

The AST in ANTLR2 looks like this:

Query:
(-1="Cuba" AND -1="its revolution")
AST:
 ( ( ( AND ( = -1 Cuba ) ( = -1 its revolution ) ) ) )

The output of the tool `antlr4-parse´ as well from the Java code gives this:

echo '(-1="Cuba" AND -1="its revolution")' | antlr4-parse InfoGuideQuery.g4 info_guide_query -tree
(info_guide_query:1 (info_guide_or_query_expression:1 (info_guide_and_query_expression:1 (info_guide_and_not_expression:1 (info_guide_query_atom:1 ( (info_guide_or_query_expression:1 (info_guide_and_query_expression:1 (info_guide_and_not_expression:1 (info_guide_query_atom:3 -1 = "Cuba")) AND (info_guide_and_not_expression:1 (info_guide_query_atom:3 -1 = "its revolution")))) ))))) <EOF>)

The Java code from src/main/java/org/oclc/test/GrammarTests.java (attached too
InfoGuideQuery.g4.txt
GrammarTests.java.txt
) produces something similar:

Running Grammar Tests
2025-03-07 07:36:08
Query: -1="perl" OR 331="titel"
ANTLR4 result:

(info_guide_query (info_guide_or_query_expression (info_guide_and_query_expression (info_guide_and_not_expression (info_guide_query_atom -1 = "perl"))) OR (info_guide_and_query_expression (info_guide_and_not_expression (info_guide_query_atom 331 = "titel")))) <EOF>)

At least consistent. But, why are the words like info_guide_query_atom from the grammar file InfoGuideQuery.g4 are part of the output?