[vidarh]

99% might have connotations like that to it, but that doesn't prevent large healthcare groups etc. from using it. E.g. Kaiser Permanente offers courses in "Mindfulness Based Stress Reduction", and so there is plenty of non-religious training material available for mindfulness meditation.

Even some of the best introductory resources on mindfulness meditation from Buddhist sources are refreshingly free of "religious-mystical-woo", or careful to separate the woo from the practice. E.g. my of my two favourite introductory resources, one (Gil Fronsdal's podcasts "Introduction to Meditation") specifically jokes about "the 'B'-word" and mentions buddhism just barely for context, and the book Mindfulness in Plain English mentions Buddhist traditions only for historical context.

As an uncompromising atheist and skeptic, this is the reason I ended up with mindfulness meditation over alternatives.

[Dewie]

The concept of a/theism might be orthogonal or irrelevant, depending on the viewpoint, to Buddhism.

By the way "uncompromising atheist and sceptic" sounds like a contradiction, at least in the sense of scepticism as the discipline of always questioning things (in general, not specifically when it comes to things like Buddhism, which I won't give an opinion about whether it is worth to investigate or not). But I guess it isn't really a contradiction if it is scepticism as in close mindedness. But it's good that you've found some material that caters to your specific sensibilities and cultural background.