That plugin is actually a macro and by pressing the Shift key while clicking on the menu item, you open the macro in the Script Editor instead of running it.

This should give you the opportunity to identify what needs to be changed. (Yes, I am asking for your assistance here... Unfortunately, I have a lot on my plate currently... but at least I hope to give you a chance to have your bug fixed faster that way.)

The OP sent this via mail by mistake rather than adding a comment in the web interface:

-- snipsnap --
Hello
There is a hidden print (IJ.log) in the following script :

eval("script", "importClass(Packages.ij.IJ);\n"
+ "\n"
+ "result = [];\n"
+ "if (IJ.getInstance() != null) {\n"
+ " importClass(Packages.fiji.User_Plugins);\n"
+ " importClass(Packages.ij.Menus);\n"
+ "\n"
+ " commands = Menus.getCommands();\n"
+ " lutsMenu = User_Plugins.getMenu('Image>Lookup Tables');\n"
+ " if (lutsMenu != null) {\n"
+ " for (i = 0; i < lutsMenu.getItemCount(); i++) {\n"
+ " menuItem = lutsMenu.getItem(i);\n"
+ " if (menuItem.getActionListeners().length == 0) {\n"
+ " // is a separator\n"
+ " continue;\n"
+ " }\n"
+ " label = menuItem.getLabel();\n"
+ " if (label.equals('Invert LUT') || label.equals('Apply LUT')) {\n"
+ " // no lookup table\n"
+ " continue;\n"
+ " }\n"
+ " command = commands.get(label);\n"
+ " if (command == null || command.startsWith('ij.plugin.LutLoader')) {\n"

Here the label list is printed from this command.

+ " result.push(label);\n"

Label is an array that contains the liste of LUT.

+ " }\n"
+ " }\n"
+ " }\n"
+ "}\n"
+ "// ImageJ's eval('script', script) erroneously always returns null\n"
+ "System.setProperty('result', result.join('\\n'));\n");
return split(call("java.lang.System.getProperty", "result"), "\n");
Hope this helps.

Hello
There is a hidden print to the log in the following script : 
eval("script", "importClass(Packages.ij.IJ);\n"
+ "\n"
+ "result = [];\n"
+ "if (IJ.getInstance() != null) {\n"
+ " importClass(Packages.fiji.User_Plugins);\n"
+ " importClass(Packages.ij.Menus);\n"
+ "\n"
+ " commands = Menus.getCommands();\n"
+ " lutsMenu = User_Plugins.getMenu('Image>Lookup Tables');\n"
+ " if (lutsMenu != null) {\n"
+ " for (i = 0; i < lutsMenu.getItemCount(); i++) {\n"
+ " menuItem = lutsMenu.getItem(i);\n"
+ " if (menuItem.getActionListeners().length == 0) {\n"
+ " // is a separator\n"
+ " continue;\n"
+ " }\n"
+ " label = menuItem.getLabel();\n"
+ " if (label.equals('Invert LUT') || label.equals('Apply LUT')) {\n"
+ " // no lookup table\n" + " continue;\n" 
+ " }\n"
+ " command = commands.get(label);\n"
+ " if (command == null || command.startsWith('ij.plugin.LutLoader')) {\n" 

Here the label list is printed from this command. 
+ " result.push(label);\n" 
Label is an array that contains the liste of LUT. 
+ " }\n"
+ " }\n
 + " }\n"
+ "}\n" + "// ImageJ's eval('script', script) erroneously always returns null\n" + "System.setProperty('result', result.join('\\n'));\n"); return split(call("java.lang.System.getProperty", "result"), "\n");
Hope this helps.

Sorry, I do not see the 'print'. I also cannot reproduce the Log output. The statement 'result.push(label)' does *not* output anything here. This is the macro I recorded so you can see exactly what I tried to reproduce:

run("Mitosis (26MB, 5D stack)");
run("Reduce Dimensionality...", "  slices frames");
run("Temporal-Color Code", "lut=Fire start=1 end=51 create");

Hello
I can reproduce by running your macro twice.
The LOG window opens and is filled with the complete list of the different LUTs.

Ah, finally the missing bit of information! The crucial bit that prevented me from reproducing was the fact that it only shows up *the second* time!

Please find the explanation of the real bug (hint: it is not that result.push() statement at all) here:

https://github.com/fiji/fiji/commit/f4dfbb51ac

Pushed and uploaded.