1. Introduction
2. Photometric and kinematic surveys of PNe in the Leo I group
2.1. Subaru SuprimeCam photometry
2.2. Extended Planetary Nebula Spectrograph (ePN.S) ETG survey
2.3. Extremely extended Planetary Nebula Spectrograph ETG survey in M105 and NGC 3384
2.4. Catalogue matching
2.5. Completeness and sources of contamination in the photometric catalogue
3. Stellar surface photometry of the Leo I group
4. Radial PN number density profile and the luminosity-specific PN number
4.1. Radial PN number density profile of M105
4.2. Two-component photometric models for the extended halo of M105
5. Constraints from resolved stellar populations
5.1. Comparing RGB number density and photometric SB profiles
5.2. Multi-component photometric models
6. Planetary nebula luminosity function of M105
6.1. PNLF variation with radius
7. Discussion and conclusions
7.1. Old, MP, and PN-rich outer halo of M105
7.2. Extended halo or IGL of the Leo I group?
7.3. Outlook