There are 4 repositories under proof-theory topic.
List of resources about foundational knowledge for programmers (supposed to last a few decades)
An adventure on formalizing logics using the Agda programming language
An exhaustive condensed detachment formal proof generator for Hilbert systems in proof theory.
DatabaseOfProofsEngine is a web application for students & researchers of math that are studying arrow-theoretic topics.
The Open Deduction Proof Editor allows proof theorists (or anyone) to deconstruction proofs step by step. It currently supports deep inference formalisms, namely Open Deduction and naturally the Calculus of Structures. The front end of the application is written in Java, while the back end is written in Maude. There is also an implementation of proof search both with and without proof variables.
Exploring the depths of mathematics through the study of its foundations
Equivalence of natural deduction and sequent calculus in HOL4
an attempt at unpacking in layman's terms what mathematics is.
An exhaustive condensed detachment formal proof generator for Hilbert systems in proof theory.
Parser for lambda terms, written in Haskell, that is also able to execute a list of operations on the terms
A reasoning system for large knowledge bases.
Prover9 is an automated theorem prover for first-order and equational logic, and Mace4 searches for finite models and counterexamples.
Housing useful resusable equations and formulas in calculus, discrete mathematics, and linear algebra.
Convert Proposition Trees to Conjunctive Normal Form (CNF) or Disjunctive Normal Form (DNF)