We currently have three tags that are essentially the same thing -- especially in a stackapps context. They are scripts, user-script, and script.
script is one of the "required tags" and has a nice wiki. From its wiki and description blurb:
User scripts for Stack Exchange sites that modify the site's behavior in the web browser. These scripts usually run in IE, Firefox, Chrome, Opera, and Safari.
The tag is clearly about userscripts. This strongly suggests that the user-script is redundant.
The user-script tag has no wiki, only has 39 questions, and all but 5 of those questions are tagged with script also. Of those 5, every one clearly fits the script tag.
Please make "user-script" a synonym of the script tag.
The scripts tag only has two questions and both of those clearly should be tagged script instead.
Please make "scripts" a synonym of the script tag.
Per the stackapps about page "This site supports the API". So all other meanings of "scripts" or "user-scripts" are either not relevant or fall under the app tag (plus, possibly, language-specific tags). (So far there have been no exceptions anyway).
Notes:
- I believe that only a moderator or dev can do this, since there are not enough power-users on stackapps for the normal synonym process.
Per this moderator's answer, this is the recommended place to ask this kind of question.
Stack Apps is for supporting the API, which includes meta discussion about it.