Phosphophyllite is a library mod used by mods in the Bigger Series, such as Bigger Reactors. By itself, it does nothing.
From the CurseForge page:
This is a library mod. It's not very useful by itself.
Phosphophyllite is licensed under the GNU Lesser General Public License, or LGPL, version 2.1.
As a TL;DR, this means you are free to:
However, you cannot:
A portion of the LGPL v2.1 license is included below. The full version of the license can be found in our GitHub's LICENSE.txt.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301