zeo conf for buildout

gistfile1.cfg

[buildout]
parts +=
    zeoserver
    client1
    client2
    cljobs 
    cldebug

[zeoserver]
recipe = plone.recipe.zeoserver
zeo-address = 8100
blob-storage = ${buildout:directory}/var/blobstorage
user = ${instance:user}

[client1]
recipe = plone.recipe.zope2instance
#debug-mode = ${instance:debug-mode}
#verbose-security = ${instance:verbose-security}
eggs = ${instance:eggs}
zcml = ${instance:zcml}
#products = ${instance:products}
environment-vars = ${instance:environment-vars}
zeo-client = on
zeo-address = ${zeoserver:zeo-address}
http-address = 8080
shared-blob = on
# Note: Do not set shared-blob = on with multiple machines.
user = ${instance:user}
http-address = 8080
debug-mode = off
verbose-security = off

[client2]
<= client1
http-address = 8081
debug-mode = off
verbose-security = off

[cljobs]
<= client1
http-address = 8090
debug-mode = off
verbose-security = off

[cldebug]
<= client1
http-address = 8091
debug-mode = on
verbose-security = on

Why define a zeo client as "cljobs" is for specific job o task? can you explain a example please?