Fugitive Doctor's TARDIS

The Fugitive Doctor travelled in a TARDIS with a police box exterior, which was readily identified by the Thirteenth Doctor as resembling her own TARDIS. It retained its police box shape even after landing in a new location. (TV: Fugitive of the Judoon)

The TARDIS was buried in an unmarked grave while the Doctor was hiding on Earth under a chameleon arch, assuming the human identity Ruth Clayton. The TARDIS was uncovered when she regained her identity. (TV: Fugitive of the Judoon)

History
While the Fugitive Doctor was under the chameleon arch, as "Ruth Clayton", the TARDIS was buried under an unmarked gravestone outside Ruth's home, a lighthouse near Gloucester.

When the Thirteenth Doctor and Ruth visited the lighthouse for answers, the Thirteenth Doctor uncovered the police box lettering of the TARDIS, to her confusion. With her Time Lord essence restored, Ruth revealed her true identity, and they teleported inside.

Soon afterwards, the Judoon's Talwak Freighter captured the TARDIS using a tractor beam. After Gat was killed, the mysterious incarnation of the Doctor returned the Thirteenth Doctor to Gloucester and went on her way. (TV: Fugitive of the Judoon)

Appearance
The interior of the TARDIS console room was reminiscent of the console room used by the First Doctor, closer to the default design, (TV: Hell Bent) though smaller, with the main screen taking up an entire wall and showing Gallifreyan symbols, and atmospheric blue lighting. (TV: Fugitive of the Judoon)

This TARDIS also had a police box exterior. The exterior did not resemble that of the Thirteenth Doctor's TARDIS, (TV: Fugitive of the Judoon) but rather the appearance it held during the time of the First and Second Doctors. (TV: An Unearthly Child et al.)

Behind the scenes

 * The TARDIS prop appears to have the exterior used by the First Doctor as played by David Bradley in Twice Upon a Time, originally created as a replica of the William Hartnell-era TARDIS for the docu-drama An Adventure in Space and Time. The TARDIS console also carries over from these productions.
 * Recently, in the Steven Moffat era, classic-style TARDIS interiors were modelled to closely resemble the First Doctor's TARDIS, making use again of the designs for An Adventure in Space and Time. Though the Fugitive Doctor's TARDIS deviates from this design aesthetic, it was nonetheless used as the basic TARDIS design later in The Timeless Children. Both the first and second TARDISes stolen by the Doctor in that story resemble this one.