The latest release (0.0.4) of SonicScrewdriveR is now on CRAN and includes two new functions for reading metadata from AudioMoth devices.
audiomoth_config() parses the CONFIG.TXT written to the microSD card during device operation.
audiomoth_wave() parses the metadata written in the Comments field of the wave file metadata. This allows easy access to time, date, temperature (if supported by firmware) and other metadata as an R list.
Please raise GitHub requests with any issues (or even requests).