f00b4r0:

commit 75ab064 'build: download code from github using archive API' introduces a new script "download.py" which is used during 'make defconfig':

26368 pts/0 S+ 0:00 | _ make V=s defconfig
26464 pts/0 S+ 0:00 | _ /bin/sh -c export MAKEFLAGS= ;make V=ss -j1 -r -s -f include/scan.mk SCAN_TARGET="packageinfo" SCAN_DIR="package" SCAN_NAME="package" SCAN_DEPS="/home/user/source/include/pac
26465 pts/0 S+ 0:00 | _ make V=ss -j1 -r -s -f include/scan.mk SCAN_TARGET=packageinfo SCAN_DIR=package SCAN_NAME=package SCAN_DEPS=/home/user/source/include/package*.mk SCAN_DEPTH=5 SCAN_EXTRA=
26806 pts/0 S+ 0:00 | _ /bin/sh -c { ?printf "\033[M\rCollecting package info: package/network/utils/arptables" >&2; echo Source-Makefile: package/network/utils/arptables/Makefile; true; make V
26807 pts/0 S+ 0:00 | _ make V=ss --no-print-dir -r DUMP=1 FEED= -C package/network/utils/arptables
26809 pts/0 R+ 0:00 | _ python /home/user/source/scripts/download.py dl_method --url https://git.netfilter.org/arptables --proto=git

This commit makes defconfig go from about 10s runtime to approx 3mn, or a ~18x slowdown.