Will backslash be removed as a quote character?

[limjcst]

Below is a test case, which is thought good

morbig/tests/good/2.6-word-expansions/2.6.3-command-substitutions/backslash-in-nested-subshells.sh

Line 3 in 2441635

echo "\""

Its corresponding expected CST, inside WordDoubleQuoted, is

morbig/tests/good/2.6-word-expansions/2.6.3-command-substitutions/backslash-in-nested-subshells.sh.expected

Line 41 in 2441635

[ [ "WordLiteral", "\\\"" ] ]

where \\\", printed as \", is exactly the content of echo "\"".
However, in bash(version 4.3.48), the output of echo "\"" is just ".

As mentioned in IEEE Std 1003.1™ - 2017, Vol. 3: Shell and Utilities, Issue 7, (Is it out of date?)

2.6.7 Quote Removal
    The quote characters (<backslash>, single-quote, and double-quote) that were present in the
    original word shall be removed unless they have themselves been quoted.

Is <backslash> removal under plan, or left to the conversion stage from concrete syntax tree to abstract syntax tree?

BTW, thanks for your brilliant work!