A catalogue of known bugs in Inform, and progress in fixing them, is currently being hosted by the Jira bug-tracking service here. Jira is a software industry standard, but takes a little patience to get used to. Users have to create accounts and log in, but this is free. Please feel free to report bugs: it’s only thanks to users taking the time to do this that we make progress in maintaining the program.
The current state of the source code for Inform sometimes contains bug fixes which haven’t yet made it into a numbered release. If you’re a command-line user of Inform and are confident in compiling your own tools, feel free. The pending release notes file usually shows the bug fixes currently waiting for the next release.
Until 2019, the Inform project used a Mantis-powered bug tracker, but this has now closed. All issues on that tracker were migrated to Jira, though their ID numbers changed in the process.