This plugin (a family of) implements the actual support for the
_DB_F_APPENDONLY page flag. When the flag is set, and this plugin
active, then ordinary users can further only append text to the
page, and won't be able to edit the earlier written parts of it. So
this implements a much softer approach than the _READONLY page

Also this plugin comes in three flavours, but you can often only
load one of them:

"appendonly" - Really allows just additions to be made to the page,
               each new separated by a horizontal bar.

"appendwrite" - Allows to insert a page separator, which protects
               the upper part from getting edited by ordinary
               users. Everything below a horizontal bar (denoted
               by at least 16 minus signs) or a double horizontal
               bar remains editable by all users.
               This plugin activates only if the _APPENDONLY and
               _WRITEABLE flag is set.

"appendcomments" - stores page additions in an separate database
               entry marked with _DB_F_PART, but allows this part
               to get edited as whole (like "appendwrite" plugin).

The last one is probably not very useful, as it generates some
overhead and in fact is a collection of various workarounds to
accomplish the desired functionality (so it may prove little
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You cannot modify the README.plugins file, but anyhow any ideas or suggestion should as usually get filed on BugReports, UserSuggestions or even better the README.plugins.Discussion.