The other Q is a bit more complex (but not very difficult) and I’m too tired right now so will pass it on to someone else. But I’d think you’d make a viewtemplate that searches the propertyfields of all other tids to match it with the title of the current tiddler.
They do not do this out of the box, but keep in mind backlinks are but one way of interlinking tiddlers. There are other such as behind the Info button. You can create a tiddler with the tag $:/tags/ViewTemplate that searches for the currentTiddler title in all fields in all tiddlers to find where it is also mentioned in fields. See https://tiddlywiki.com/#search%20Operator%20(Examples)
The title can be anything.
The tag makes it into a viewtemplate that appears in all tiddlers (altho nothing to show for most) list-after ensures it is shown at bottom of tiddler.
The code is probably self explanatory.
It works as expected. Then I tried it without the blank line before </list> and it does not work, which seems a bit strange as often a blank row in the block of code can cause code to fail. So, what is the logic/syntax that is going on here?
If the list widget is empty with one blank line it defaults to a simple template. Otherwise you may put <$link/><br> inside to get the same result.
If you set a list-after or list-before field it changes the order within which the tagged tiddlers are listed. If empty it will go towards the top or bottom of the list.
In the top example of yours this is indicating the content of fields title tags etc. You set them to the value after :
This is why I explained these in my previous post.
In general, tiddlyWiki and “code discussions” use a syntax like so
fieldname: value
so, for example
title: Foo
simply means that the field title in a tiddler has the value Foo.
You can see this is if you export a tiddler (tiddler tool more > Export tiddler > .tid format) and read the resulting file in a text editor.
If you have created a custom field, like your ´properties´ field, then this will appear just as any other field in that exported tiddler.
Right, the blank line in the otherwise empty listwidget content is a convenience to show the resulting output with a newline. It is equivalent to inserting <$link/><br> there.
If you want the output without the linebreaks, then you can omit the empty row but you must really omit it, i.e no other string must be there.
If you do still insert a string, e.x X then this string will show in place of the output result. If the string is a space character, i.e <$list filter="..."> </$list> (note the space between the two tags) then the output of multiple space characters is not very visible, just like if you type in multiple space chars in the text of a tiddler.
You are evidently not quite familiar with the syntax so I’d suggest reading up on this via the various introductory sources you can find on tiddlywiki.com . This should give a more structured explanation of things which probably is better than a fragmented one from people replying to details like in this thread, but you’re of course always welcome to ask more here if things are unclear.