Note
 All of the following ZDB attributes can be set with $db attr commands, e.g. 
$db attr $oid set {@comment=MY COMMENT}

@comment and @commentclickaction Object Attributes

Textual comments can be attached to objects using the @comment attribute. The attribute can be added/modified via the GUI’s popup menu (i.e. Edit › Add Comment …​). Objects with an @comment attribute are displayed with a "speech bubble" icon Comment in certain windows (e.g. in the Mem window); the attribute value is also displayed in tooltips.

Comment icon in the Mem window

If the option Show Comments is enabled via the Preferences dialog, objects' comments are graphically displayed in Schem and Cone windows with speech bubbles. If such a "speech bubble" is clicked, the value of the object’s @commentclickaction attribute is evaluated as a Tcl script (if the attribute exists).

Comment speech bubble in the Schem window

@name Object Attribute

If an object has a @name attribute, its value will be displayed in the Schem and Cone windows instead of the original name.

@cell Instance Attribute

If an instance has a @cell attribute, its value will be displayed in the Schem and Cone windows instead of the original cell name.

@encrypted Module Attribute

Modules with an @encrypted attribute are displayed with a red padlock to indicate that their contents are encrypted.

An encrypted module

@PARAMETERS Cell Attribute

If a cell has a @PARAMETERS attribute, the attribute’s value is displayed in a "Parameters" section in the Tree window. The RTL parser automatically adds this attribute for parameterized modules.

Tree window with parameters

@GROUP_NAME Module Attribute

In the Tree window, instances flagged with the group flag will grouped in a special node "Custom Group". You can change this node’s name by setting the parent module’s @GROUP_NAME.

Tree window with custom grouping