Problem with left over files from earlier releases

After the latest round of package upgrades sysutils/vm-bhyve and graphics/digikam failed 
to start with the error:

ld-elf.so.1: /usr/lib/libelf.so.1: version ELFUTILS_1.0 required by /usr/local/lib/libdw.so.1 not 
found

Digging around for libelf.so I found:

curlew:/home/mike% locate libelf.so.1
/usr/lib/libelf.so.1
/usr/local/lib/libelf.so.1
curlew:/home/mike% ls -l /usr/lib/libelf.so.1 /usr/local/lib/libelf.so.1
-r--r--r--  1 root  wheel  90760 30 Apr  2016 /usr/lib/libelf.so.1
lrwxr-xr-x  1 root  wheel     15  2 Apr 02:42 /usr/local/lib/libelf.so.1@ -> libelf-0.187.so

It looks like seven year old /usr/lib/libelf.so.1 is left over from an old version. Booting from 
a memstick image confirms there is no /usr/lib/libelf.so.1 in 'out of the box' FreeBSD 13.1 
so I deleted it and both programs worked. But this makes me wonder how many 
redundant old files might be lying around in the base system and potentially causing 
problems. Is there any easy way to track these down other than doing a fresh install from 
scratch? Since I'm intending to upgrade to 13.2 soon this could be a good time to see if 
there's more redundant stuff to clean out.

-- 
Mike Clarke