/usr/mipsel-linux-gnu/bin/readelf is in binutils-mipsel-linux-gnu 2.28-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/mipsel-linux-gnu/bin/../../bin/mipsel-linux-gnu-readelf
/usr/mipsel-linux-gnu/bin/../../bin/mipsel-linux-gnu-readelf