This package defines LGitCallback and provides an implementation of #’initializeNull’. It also provides an extension that has an implementation of #’beNull’. Where is the variable ’thunk’ defined? Why is this in an extension? https://github.com/pharo-vcs/libgit2-pharo-bindings/blob/master/LibGit-Core.... instance initialization initializeNull self beNull https://github.com/pharo-vcs/libgit2-pharo-bindings/blob/master/LibGit-Compa... *LibGit-Compatibility-Pharo7 beNull thunk := ExternalAddress null