To cite package ‘ggExtra’ in publications use:

  Attali D, Baker C (2024). _ggExtra: Add Marginal Histograms to
  'ggplot2', and More 'ggplot2' Enhancements_. R package version
  0.10.1.9000, , <https://github.com/daattali/ggextra>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {ggExtra: Add Marginal Histograms to 'ggplot2', and More 'ggplot2'
Enhancements},
    author = {Dean Attali and Christopher Baker},
    year = {2024},
    note = {R package version 0.10.1.9000, 
},
    url = {https://github.com/daattali/ggextra},
  }