About removing group identifiers from subject line

[Harry Putnam <reader@newsguy.com>]

the group illumos-developers on gmane is one of those where the list
server puts a tag in subject line.  In this case:
`[illumos-developer]'

So a subject line may be 
  Subject: [illumos-developer] blah bug fix blah when

In our manual in the `Group Parameters' section I see this info (ONLY
PARTIAL):

[...]

,----
|      A use for this feature is to remove a mailing list identifier tag
|      in the subject fields of articles.  E.g. if the news group
| 
|           nntp+news.gnus.org:gmane.text.docbook.apps
| 
|      has the tag `DOC-BOOK-APPS:' in the subject of all articles, this
|      tag can be removed from the article subjects in the summary buffer
|      for the group by putting `(gnus-list-identifiers "DOCBOOK-APPS:")'
|      into the group parameters for the group.
`----

[...]


(I'm assuming where it says `DOCBOOK' in the last sentence... its a
typo and should say `DOC-BOOK')

But that aside, adding the line below to Group Parameters appears to
have no effect:

((gnus-list-identifiers "[illumos-developers]"))

All the subject lines still have `[illumos-developers]' in them

-------        ---------       ---=---       ---------      -------- 

There is a whole section above what I quoted above, that may mean some
other step needs to be taken too... I really couldn't understand what
that section is trying to tell me.

Posting more context below;  Maybe someone will know how this is
supposed to work:

From section Group Parameters
,----
| [...]
| 
| `(VARIABLE FORM)'
|      You can use the group parameters to set variables local to the
|      group you are entering.  If you want to turn threading off in
|      `news.answers', you could put `(gnus-show-threads nil)' in the
|      group parameters of that group.  `gnus-show-threads' will be made
|      into a local variable in the summary buffer you enter, and the
|      form `nil' will be `eval'ed there.
| 
|      Note that this feature sets the variable locally to the summary
|      buffer if and only if VARIABLE has been bound as a variable.
|      Otherwise, only evaluating the form will take place.  So, you may
|      want to bind the variable in advance using `defvar' or other if
|      the result of the form needs to be set to it.
| 
|      But some variables are evaluated in the article buffer, or in the
|      message buffer (of a reply or followup or otherwise newly created
|      message).  As a workaround, it might help to add the variable in
|      question to `gnus-newsgroup-variables'.  *Note Various Summary
|      Stuff::.  So if you want to set `message-from-style' via the group
|      parameters, then you may need the following statement elsewhere in
|      your `~/.gnus.el' file:
| 
|           (add-to-list 'gnus-newsgroup-variables 'message-from-style)
| 
|      A use for this feature is to remove a mailing list identifier tag
|      in the subject fields of articles.  E.g. if the news group
| 
|           nntp+news.gnus.org:gmane.text.docbook.apps
| 
|      has the tag `DOC-BOOK-APPS:' in the subject of all articles, this
|      tag can be removed from the article subjects in the summary buffer
|      for the group by putting `(gnus-list-identifiers "DOCBOOK-APPS:")'
|      into the group parameters for the group.
`----