(responding to Ed)
> From memory.....
> I recall they link places such as
> /usr/include and others which would be needed
> to properly generate a stack trace.

Hmmm...  This gives me an idear.  Let me try something.  I'll vi the output from
ls -alR | grep "^l" > output.txt
I'll list my steps below in case something I do doesn't do what I think.  (there may be typos in what follows. there were mis-steps, I did not include those)

1. :1,$s/^...........//   (removes permissions string from beginning of each line)

2. :1,$s/^ \+1 abrt abrt//   (removes variable number of spaces and "1 abrt abrt) from beginning of each line)

3. :1,$s/^ \+ \d\+ \a\a\a \+\d\+ \+....//   (removes variable number of spaces, 1 or 2 digit number, variable number of spaces, and date from beginning of each line)

4. :1,$s/ \S\+ -> //   (removes space, file or directory name, and " -> " from beginning of each line)  Each line should now contain only the destination of each link, what each link was pointing to.  I notice that many lines now start with repeats of "../", but many do not (that's odd!).

The above 4 steps altered every line in the file.

5. Now I'm gonna assume that all the "../" repeats take us to '/', and try to replace those with'/'.  This should make each file or path absolute.
:1,$s/^\(\.\.\/\)\+/ROOT/:1,$s/
That was difficult.  Changed 12380 out of 13827 lines, so only 12380 links were to a different path.

6. :1,$s/ROOT/\//   (changes "ROOT" at the beginning of the line to '/'; results after this step are saved into a separate file)

Now how can I get the names off the end of each line?  End-of-line names have letters, digits,'-', '+', '_', and '.';  hopefully no others.  Unfortunately, in some cases, there's no way of knowing whether the name is a file name or a directory name.

7. :1,$s/[a-zA-Z0-9\.\_\-\+]\+$//   (removes file (and directory?) names from end of each line; results after this step are saved into a separate file)

Now I want to sort the results and remove duplicate lines.

8. sort -f link_destdirs.txt > destdirs_sorted.txt

9. uniq -c destdirs_sorted.txt > unique_destdirs.txt

I fpasted the results here:
"https://paste.centos.org/view/6dc39f3d"
Summary:
* Ed was partially correct: many of the links point to somewhere under "/usr/", but none to "/usr/include/" or anywhere underneath.
* Some of the links seem to point to somewhere under /.build-id/", but I'm suspicious that the process used above might be mis-leading us on this.  I don't see a ".build-id" under '/' on my system.
* Many of the links point to somewhere under "/lib64/".
* Some of the links point to somewhere under "/libexec/" (suspicious).
* Other destinations listed are "/.dwz/" (suspicious), "/bin/", "/sbin/", "/share/" (suspicious), "/system-generators/" (suspicious), "/systemd/" (suspicious), and, "/udev/" (suspicious).
* 997 of the links seem to not point to some other directory.
* Overall, there appears to be 1243 different link destinations.
The suspicious results may be because I made wrong assumptions in steps 4 and 5.  My comment between steps 6 and 7 might also be relevant.

It took a few hours to figure out the above process.  That's as much of an answer as I can give to Samuel's question:
> Where do they link to?
Is there a way of getting a better answer?

So how do I safely get rid of everything under /var/cache/abrt-di/usr/, including what the 13800+ links are pointing to?

thanks,
Bill.