As you may guess, the pig headed user which I am was not satisfied to read that the dictionaries were probably out of date.
So I asked EasyFind to scan the contents of the System folder for the string "attach action".
Of course seeing SystemEvents.sdef here was puzzling because when I ask the Script Editor to display System Events dictionary I see no "attach action" command.
<suite name="Hidden Suite" code="tpnm" description="Hidden Terms and Events for controlling the System Events application" hidden="yes">
<class-extension extends="folder" description="The Folder Actions specific extensions to the folder class" hidden="yes">
<responds-to command="attach action to">
<cocoa method="attachActionVerb:" />
</responds-to>
<responds-to command="attached scripts">
<cocoa method="attachedScriptsVerb:" />
</responds-to>
<responds-to command="edit action of">
<cocoa method="editActionVerb:" />
</responds-to>
<responds-to command="remove action from">
<cocoa method="removeActionVerb:" />
</responds-to>
</class-extension>
<class-extension extends="folder action" description="An action attached to a folder in the file system">
<property name="has new changes" code="hnch" type="boolean" access="r" description="Used to check if there have been files added or removed since the action was disabled or created." />
</class-extension>
<command name="attach action to" code="facoatfa" description="Attach an action to a folder" hidden="yes">
<cocoa class="AttachActionVerb" />
<direct-parameter type="specifier" description="the object for the command" />
<parameter name="using" code="faal" type="text" description="a file containing the script to attach">
<cocoa key="using" />
</parameter>
<result type="folder action" />
</command>
<command name="attached scripts" code="facolact" description="List the actions attached to a folder" hidden="yes">
<cocoa class="AttachedScriptsVerb" />
<direct-parameter type="specifier" description="the object for the command" />
<result>
<type type="any" list="yes" />
</result>
</command>
<command name="cancel" code="prcscncl" description="cause the target process to behave as if the UI element were cancelled" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<result type="UI element" />
</command>
<command name="confirm" code="prcscnfm" description="cause the target process to behave as if the UI element were confirmed" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<result type="UI element" />
</command>
<command name="decrement" code="prcsdecr" description="cause the target process to behave as if the UI element were decremented" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<result type="UI element" />
</command>
<command name="do folder action" code="facofola" description="Send a folder action code to a folder action script" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<parameter name="folder action code" code="actn" type="actn" description="the folder action message to process">
<cocoa key="code" />
</parameter>
<parameter name="with item list" code="flst" type="any" optional="yes" description="a list of items for the folder action message to process">
<cocoa key="itemList" />
</parameter>
<parameter name="with window size" code="fnsz" type="rectangle" optional="yes" description="the new window size for the folder action message to process">
<cocoa key="windowSize" />
</parameter>
</command>
<command name="do script" code="miscdosc" description="Execute an OSA script." hidden="yes">
<cocoa class="DoScriptVerb" />
<direct-parameter description="the object for the command">
<type type="alias" />
<type type="file" />
<type type="text" />
</direct-parameter>
<result type="any" />
</command>
<command name="edit action of" code="facoedfa" description="Edit an action of a folder" hidden="yes">
<cocoa class="EditActionVerb" />
<direct-parameter type="specifier" description="the object for the command" />
<parameter name="using action name" code="snam" type="text" optional="yes" description="...or the name of the action to edit">
<cocoa key="usingName" />
</parameter>
<parameter name="using action number" code="indx" type="integer" optional="yes" description="the index number of the action to edit...">
<cocoa key="usingNumber" />
</parameter>
<result type="file" />
</command>
<command name="increment" code="prcsincE" description="cause the target process to behave as if the UI element were incremented" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<result type="UI element" />
</command>
<command name="key down" code="prcskeyF" description="cause the target process to behave as if keys were held down" hidden="yes">
<cocoa class="KeyDownVerb" />
<direct-parameter type="any" description="the object for the command" />
</command>
<command name="key up" code="prcskeyU" description="cause the target process to behave as if keys were released" hidden="yes">
<cocoa class="KeyUpVerb" />
<direct-parameter type="any" description="the object for the command" />
</command>
<command name="pick" code="prcspick" description="cause the target process to behave as if the UI element were picked" hidden="yes">
<direct-parameter type="specifier" description="the object for the command" />
<result type="UI element" />
</command>
<command name="remove action from" code="facormfa" description="Remove a folder action from a folder" hidden="yes">
<cocoa class="RemoveActionVerb" />
<direct-parameter type="specifier" description="the object for the command" />
<parameter name="using action name" code="snam" type="text" optional="yes" description="...or the name of the action to remove">
<cocoa key="usingName" />
</parameter>
<parameter name="using action number" code="indx" type="integer" optional="yes" description="the index number of the action to remove...">
<cocoa key="usingNumber" />
</parameter>
<result type="folder action" />
</command>
<enumeration name="actn" code="actn" hidden="yes">
<enumerator name="items added" code="fget" description="items added" />
<enumerator name="items removed" code="flos" description="items removed" />
<enumerator name="window closed" code="fclo" description="window closed" />
<enumerator name="window moved" code="fsiz" description="window moved" />
<enumerator name="window opened" code="fopn" description="window opened" />
</enumeration>
</suite>