There are more than one technical elements used here: the infrared film, the red filter, the lith developer on print paper. Each one can be used alone to give some 'unusual'/creative result.
The infrared negative film accentuates higher temperature objects compared to cooler ones.
The deep red filter blocks blue light, leaving mostly red and infrared to reach the film. This gives a tone balance that is strange and unexpected compared to what the human eye is able to catch. A deep red filter can be used with regular panchromatic negatives too, making red flowers to look almost white on the prints, with a contrast higher than usual. Another interesting use for the deep red filter can be in taking photos in the fog, with a longer pose time. It helps revealing image parts from far away, that are invisible to the eye due to the fog. This is because infrared is less disturbed by the humidity that the visible light spectra.
The lith developer is associated to high contrast images, ideally only 2-tone (black and white without intermediate/grey). However from my experience that 2-tone only image could be achieved with special high contrast 'lith' films that are/were used in graphic arts. I did some experiments in the past (long ago), with a special lithography developer (Agfa HC10), highly alcaline, together with the Agfaortho 25 professional film (35mm) as well as usual panchromatic film (perhaps Agfapan professional 100 or 25). The result was a somehow higher contrast negative. Especially with Agfaortho that was an all-clear base film (not milky one as other negatives), I remember a remaining warm tone on the gelatin.
Your print includes all three techniques. What is directly lit by the sunlight appears almost white. The infrared film makes this and the red filter helps. The lith developer seems to leave that pink tone on the printing paper (perhaps associated to a longer processing time ? ). The result is this lovely photo!