Seems like the docs in the Jenkins plugin page has been improved a bit. (Version: 2.92)
Triggers By default, the only trigger configured is the Failure - Any
trigger. To add more triggers, select one from the drop-down and it
will be added to the list. To see what conditions must be met for this
plugin to send an email, click on the "?" (question mark) next to the
trigger.
Extended Email Publisher Triggers The following triggers are available
as part of the Extended Email Publisher plugin, other plugins can
provide triggers as well through the extension point defined in the
Extended Email Publisher:
Aborted An email will be sent if the build status is "Aborted". A
build is aborted via the UI or API, but normally requires some sort of
user intervention to occur. An aborted build is stopped during its
execution.
Always Always triggers an email after the build, regardless of the
status of the build.
Before Build An email will be sent when the build begins, but after
SCM polling has completed.
Failure → Unstable (Test Failures) An email will be sent any time the
build goes from failing (compilation or build step failures), to
unstable (unit test failures). This basically means that all the
builds steps were successful, but there are still tests failing.
Failure - Any An email will be sent any time the build fails. If the
"Failure - Still" trigger is configured, and the previous build status
was "Failure", then the "Failure - Still" trigger will send an email
instead.
Failure - 1st An email will be sent when the build status changes from
"Success" to "Failure".
Failure - 2nd An email will be sent when the build fails twice in a
row after a successful build.
Failure - Still An email will be sent if the build status is "Failure"
for two or more builds in a row.
Failure - X An email will be sent when the build fails X times in a
row after a successful build
Fixed An email will be sent when the build status changes from
"Failure" or "Unstable" to "Success".
Not Built An email will be sent if the build status is "Not Built".
This status code is used in a multi-stage build (like maven2) where a
problem in earlier stage prevented later stages from building.
Script - After Build Allows the user to define a script that is
executed to determine if an email should be sent AFTER the build
occurs. The last line of the script should resolve to true to send an
email, or false to not send an email. See Script Trigger Options below
for parameters available to the script.
Script - Before Build Allows the user to define a script that is
executed to determine if an email should be sent BEFORE the build
occurs. The last line of the script should resolve to true to send an
email, or false to not send an email. See Script Trigger Options below
for parameters available to the script.
Status Changed An email will be sent if the build status changes.
Success An email will be sent if the build status is "Successful". If
the "Fixed" trigger is configured, and the previous build status was
"Failure" or "Unstable", then the "Fixed" trigger will send an email
instead.
Test Improvement An email will be sent any time there is an
improvement. A build is considered to have improved whenever it has
fewer test failures than the previous build. If the current failure
count went to 0 (no more test failures) this trigger will NOT send an
email.
Test Regression An email will be sent any time there is a regression.
A build is considered to regress whenever it has more failures than
the previous build, or if there are new tests that failed.
Unstable (Test Failures) An email will be sent any time the build is
unstable. A build is unstable if there are test failures, but all the
build steps completed successfully. If the "Unstable - Still" trigger
is configured, and the previous build status was "Unstable", then the
"Unstable - Still" trigger will send an email instead.
Unstable (Test Failures) - 1st An email will be sent when the build
status changes from anything to "Unstable".
Unstable (Test Failures) - Still An email will be sent if the build
status is "Unstable" for two or more builds in a row. A build is
unstable if there are test failures, but all the build steps completed
successfully.
Unstable (Test Failures)/Failure → Success An email will be sent when
the build status changes from "Failure" or "Unstable" to "Success".
Intermediate "Aborted" builds are ignored.