In order to implement a successful user interface to do the time-frequency source space viewing, I thought it was necessary to synchronize among MNE GUIs so understanding the other GUIs well and working on the backend renderer was the theme for this week. First, I recorded a YouTube tutorial embedded in the documentation for the coregistration user interface https://github.com/mne-tools/mne-python/pull/10802. There were a few road blocks from failing CIs https://github.com/mne-tools/mne-python/pull/10825, https://github.com/mne-tools/mne-python/pull/10824 that had to be fixed as well. Then, the real workload was refactoring the backend so that it works on both notebook and pyvistaqt https://github.com/mne-tools/mne-python/pull/10803 for when the time-frequency viewer is added. This was quite a bit of work but is almost done, and cleans up the code tremendously.