### I just built a Sage system. What files may I delete with impunity?

I have just built Sage 7.6 on an Apple iMac 8,1 running OS X version 10.11.6. I started with a download of a compressed source distribution from the Sage github repository (without cloning the repository itself, since I don't yet plan to contribute any development ideas or comments for awhile). Doctesting went very well, with only two failed tests out of the entire suite:

```
sage -t src/sage/doctest/test.py # 1 doctest failed
sage -t src/sage/modules/vector_rational_dense.pyx # 1 doctest failed
```

I also downloaded the equivalent binary distribution and doctested that, obtaining these results:

```
sage -t src/sage/calculus/calculus.py # 1 doctest failed
sage -t src/sage/doctest/test.py # 1 doctest failed
sage -t src/sage/graphs/digraph_generators.py # 3 doctests failed
sage -t src/sage/graphs/graph_generators.py # 5 doctests failed
sage -t src/sage/graphs/hypergraph_generators.py # 7 doctests failed
sage -t src/sage/modules/vector_rational_dense.pyx # 1 doctest failed
sage -t src/sage/tests/cmdline.py # Timed out after testing finished
```

I did expect my own build to do better, but the installation I ended up with is fully 2 GB larger than what came in the binary distribution. Much (more than 1/3) of the overage is in a directory

```
../sage-7.6/local/share/doc/sage/doctrees
```

which is not present in the binary distribution, and I assume it is only of interest to developers. Is that correct? I will trim my build by also removing two large files

```
../sage-7.6/src/build/temp.macosx.10.9...
../sage-7.6/src/build/lib.macosx.10.9...
```

but keep my log and upstream files in case I want to review the build or look at the sources. All this is pending any further advice I get in the next few days about files that are generally only of interest to developers.