When the user creates a signal based on your plug-in, they are presented with a signal editor dialog to allow them to configure your plug-in. These strings describe the configuration options and their parameters. If the plug-in is a mini-plug-in, these items are added to the pre-parser's items and this section might be minimal or even empty. If this plug-in is a full-plug-in (based on RAW data), this section will include every option needed to extract and interpret the data (which channels are being used and for what purpose, the BAUD rate, clock polarity...)
Each configuration option LABEL in your plug-in should be unique. Also, if you are using one of the built-in pre-processors, your labels should not conflict with its labels. The labels are displayed to the user and are also used for internal reference.
(see: Configuration Editors for Available editors and their configuration syntax)