I haven't see a lot of job postings for those. It's either a dedicated security professional, or a software engineer.
I once worked for company making a security product. The other software engineers knew almost nothing about security or secure coding practices. It was never a requirement for the company to hire people with security skills, nor did security skills even get taught! I tend to think that's the norm in the industry, but I'd be happy to be proven wrong.
I have one of those jobs, which is why I brought it up :P I am a software engineer and provide security direction to a team of "pure" software engineers (who are slowly getting better at security). Sometimes I help them with the implementation of things.
Other security adjacent roles can be found in areas like web browsers, compilers, and kernels; there's a massive amount of software engineering work that goes into securing existing systems that goes beyond trying to break things. Most large companies will have many people working in such roles.
I once worked for company making a security product. The other software engineers knew almost nothing about security or secure coding practices. It was never a requirement for the company to hire people with security skills, nor did security skills even get taught! I tend to think that's the norm in the industry, but I'd be happy to be proven wrong.