Identifying cause of local package build

[Skyler via <help-guix@gnu.org>]

Hello,

Recently (since at least this past weekend) when I try to `guix system reconfigure` or `guix home reconfigure`, my machine tries to do a local build of inkscape and ends up failing (I suspect this is due to low resources available on my machine as the log simply says that it was killed by a signal, but I did not see any compiler errors). My guix config is a little complicated (although I only have one custom package, and it is a vim extension which declares no inputs) so I am trying to track down the reason for this build. I do not have inkscape explicitly installed, so there must be something that depends on it.

When I try `guix shell inkscape`, a substitute is downloaded successfully. So I assume that there is some inkscape variant that is needed somewhere. I tried to find the reason for this with the following:

```
> guix gc --referrers /gnu/store/j2g2vwf3h1r0pn0l6y95qr4lis5y03h9-inkscape-1.2.1.drv
/gnu/store/009i7sq1df9q05i7hfk07axphabnsgrw-dblatex-0.3.12.drv
/gnu/store/7w4i4ss6c3bncav8gq87bs3x4c8lrvi9-dblatex-0.3.12.drv
/gnu/store/z4gr7lzsxis1yxr5sgxxfb8rpgp57fxd-dblatex-0.3.12.drv/gnu/store/zfk84536nvnpp4f2q2gz51wmb98ik2h4-dblatex-0.3.12.drv
```

The only thing that requires this variant of inkscape is dblatex. But `guix shell dblatex` also succeeds with only substitute downloads. I checked ci.guix.gnu.org and the most recent inkscape build on master for my architecture succeeded (http://ci.guix.gnu.org/build/369838/details), but this build ran 3 months ago. I tried searching for the derivation hash j2g2vwf3h1r0pn0l6y95qr4lis5y03h9 and got no results, but I think that this might not be an expected use of the search bar. I also tried deleting the ~/.cache/guix directory and pulling again, but this resulted in the same behavior.

Is there an efficient way to track down what is causing this inkscape to be built, aside from manually running `guix gc --referrers` on every derivation until I (hopefully) find something that leads me to the root cause?

My system is:

```
Generation 38 Apr 28 2023 14:23:04 (current)
guix 4884ee6
repository URL: https://git.savannah.gnu.org/git/guix.git
branch: master commit: 4884ee6dd4b1694a4a502dd8058d6c61fa0c0199

```

Thanks,
Skyler