diff --git a/docs/manual/log-filters/key-value-data.md b/docs/manual/log-filters/key-value-data.md
index 65a3ee5c4..786e3fe35 100644
--- a/docs/manual/log-filters/key-value-data.md
+++ b/docs/manual/log-filters/key-value-data.md
@@ -15,6 +15,7 @@ There are only three configuration components:
   - Pattern
   - Name Data
   - Log Data (Checkbox)
+  - Match Substrings (Checkbox)
 
 The Pattern field matches a regular expression and looks for one or two Capture Groups. If there are two Capture Groups, the first will be mapped to a Rundeck variable key in the data context, while the second will be the value. If there is only one Capture Group, the match will be the value.
 
@@ -22,6 +23,8 @@ The Name Data field is only used when a single Capture Group is defined in the r
 
 Log Data is a checkbox that, if checked, will add tabular output of what is captured in the filter to the log output of the job that the filter is attached to.
 
+Match Substrings is a checkbox that, if checked, will allow the Pattern to match substrings within a line of log output. If unchecked, the Pattern must match the entire line of log output.
+
 By default, the pattern field is set to: `^RUNDECK:DATA:(.+?)\s*=\s*(.+)$`
 
 This will match output of the attached job if there is a line in the log output that begins with _RUNDECK:DATA:foo=value1_. The data is available in later job steps as the Rundeck variable `$data.foo` with a value of everything after the equals sign to the end of the line. So in this case, the value of `$data.foo` would be _value1_.