This file is indexed.

/usr/lib/xymon/client/local/README is in xymon-client 4.3.25-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
This directory - the client/local/ directory - can be used to
install Xymon client add-on scripts. The Xymon client will run
all files in this directory that are executable, and include the
output from each script in a separate section in the Xymon client
message which is sent to the Xymon server.

This output will have to be processed on the Xymon server; there
is no default processing done by Xymon on the output from these
scripts. They are merely added to the client data.

If you want to install an add-on script that direcly generates a 
status column in Xymon, this should go in the client/ext/ directory
instead.