It's kind of broken (I'll get to that), but even if it wasn't, it doesn't do what you think.
With an artificial, but comparable, example of it, take this query:
select code from
(
select 1 id, 'abc' code from dual
union all
select 2 id, 'xyz' code from dual
union all
select 3 id, 'def' code from dual
) subq
where
LTRIM(RTRIM(UPPER(subq.code))) < LTRIM(RTRIM(UPPER('b')));
This is the 'BEFORE' clause at work. My subquery is pretending to be a bunch of resources that have the code abc, def, and xyz.
You're expecting that 'AFTER B' would capture B% or B* but in fact it performs a greater-than check instead. If you did that in the query above, it would return resources def, and xyz. 'abc' would not be returned because it is equal to or less than B.
The clause I put above for 'BEFORE B' would return only resource 'abc' and exclude the others. As such, it should work best on dates, rankings, and sequential status/progress indicators.
However it won't because of a bug in that the XOG expressions have an 'ESCAPE' clause added to them as well. This is the broken part, like this:
...
LTRIM(RTRIM(UPPER(subq.code))) > LTRIM(RTRIM(UPPER('b'))) ESCAPE '/';
This errors out with an ORA-907 missing right parenthesis, which is a bit odd as far as messages go, but it's correct to say this is an error. The only time you need/want an ESCAPE clause is for LIKE comparisons because they can contain wildcard characters like % and _ and if your input data contains REAL % or _ you wouldn't want it to be turned into a wildcard by mistake.
These clauses however are not LIKEs and therefore it's not valid to try and ESCAPE them, and can give you results like the following especially on a text field:
<NikuDataBus xsi:noNamespaceSchemaLocation="../xsd/nikuxog_resource.xsd">
<Header externalSource="NIKU" version="15.4.1.115"/>
<Resources/>
<XOGOutput>
<Object type="resource"/>
<Status state="FAILURE"/>
<Statistics failureRecords="0" insertedRecords="0" totalNumberOfRecords="0" updatedRecords="0"/>
<Records>
<Record>
<KeyInformation/>
<ErrorInformation>
<Severity>FATAL</Severity>
<Description>Resource Object read failed</Description>
<Exception>SQL Exception with error code : 907</Exception>
</ErrorInformation>
</Record>
</Records>
...
</XOGOutput>
</NikuDataBus>